Comprehensive Guide to Modal Verbs, Adjectives, Passive Voice, and Relative Pronouns

Modal Verbs of Permission, Possibility, and Obligation

Modal verbs are functional words used to express various degrees of certainty, ability, permission, and necessity. In terms of seeking and granting permission, common modals include "can" and "may." The term "can" is frequently used for general permission, while "may" is often employed in more formal contexts. Other related terms in this category include "would" and "could." For advice or moral obligation, the expressions "should" and "ought to" are used interchangeably. Strong obligation or necessity is expressed using "must."

In addition to pure modal verbs, several phrasal expressions function similarly. "Be able to" denotes capacity or ability. "Be supposed to" indicates an expectation or an underlying rule. Permission can also be expressed through the phrases "be allowed to" and "be permitted to." When discussing the likelihood or possibility of an event, "may" indicates a high degree of certainty, specifically a $90\%$ probability. In contrast, "might" represents a much lower level of possibility, estimated at only a $5\%$ probability.

Expressions of necessity also include "have to" and the more informal "have got to." The phrase "had better" is used to provide strong advice or warnings. Other common modal auxiliary components found in English include "shall," "will," "must," and the combination "might win."

Comparative and Superlative Adjectives

Adjectives are modified to compare two or more entities using comparative and superlative forms. For short, one-syllable adjectives (or two-syllable adjectives ending in "-y"), the comparative is generally formed by adding the suffix "-er" and the superlative by adding the suffix "-est."

The following examples illustrate these transformations: "easy" becomes "easier" and "the easiest"; "dark" becomes "darker" and "the darkest"; "tall" becomes "taller" and "the tallest"; "funny" becomes "funnier" and "the funniest"; "small" becomes "smaller" and "the smallest"; "fast" becomes "faster" and "the fastest"; "big" becomes "bigger" (with a doubled consonant) and "the biggest"; "cool" becomes "cooler" and "the coolest"; and "short" becomes "shorter" and "the shortest." Other adjectives following similar patterns include "thin," "cheap," "old," "lucky," "happy," and "cad."

For longer adjectives, typically those with three or more syllables, the comparative is formed using the word "more" before the adjective, and the superlative is formed using "the most." Adjectives that fall into this category include "beautiful," "interesting," "amazing," "dangerous," "intelligent," "remarkable," "decorated," "expensive," "responsible," "famous," and "exciting." Examples of comparative usage in interrogative forms include: "Which is the longest river?" (superlative) and "Which river is longer?" (comparative).

Interrogative Structures in the Past Perfect Tense

The past perfect tense is used to describe actions that were completed before another action in the past. It follows the structure of "had" followed by the past participle. Examples of information questions include: "What had she cooked before I called you?"; "Where had you gone before I arrived?"; and "What had done?" (referencing a completed action). In response to temporal queries, such as "When had you arrived?", a typical response would be "I had already cleared the house." For queries regarding subjects, an example is: "Who had gone to the pool after eaten?"

Passive Voice Transformation and Tense Review

The passive voice shifts the focus from the performer of the action (the subject) to the recipient of the action (the object). This is achieved by using a form of the verb "to be" followed by the past participle. Consider the active sentence: "The hospital is going to give a case to the doctor." This can be transformed through various tenses in the passive voice.

In the simple present, the structure is: "A case is given to the doctor by the hospital." In the simple past, it becomes: "A case was given to the doctor by the hospital." For progressive (continuous) tenses, the forms are: "A case is being given to the doctor by the hospital" (present progressive) and "A case was being given to the doctor by the hospital" (past progressive). In the present perfect, the transformation is: "A case has been given to the doctor by the hospital." For conditional or modal usage, it is: "A case would be given to the doctor by the hospital." For the future using "going to," the structure is: "A case is going to be given to the doctor by the hospital."

A secondary example follows the active sentence: "My father gave a car to Maria." The passive transformations include: "A car is given to Maria by my father" (Simple Present); "A car was given to Maria by my father" (Simple Past); "A car is being given to Maria" (Present Progressive); "A car was being given to Maria" (Past Progressive); "A car has been given to Maria" (Present Perfect); "A car would be given to Maria" (Conditional/Modal); "A car is going to be given" (Future with "going to"); and "A car will be given" (Simple Future).

Relative Pronouns and Usage

Relative pronouns are used to connect a clause or phrase to a noun or pronoun, providing additional information. The choice of pronoun depends on whether the referent is a person, place, thing, time, or possessive entity.

"When" is used to refer to time, as in the example: "When I study, I learn more." "Where" is used for places, such as: "S.D. [Santo Domingo] is the place where I like." "Who" is utilized for people, illustrated by: "Rosa is the person I was talking to" (alternatively, "the person who I was talking to"). "That" refers to things or topics, for example: "The topic that I prepared." "Which" is used for non-human things or to provide extra information about a noun: "Megacentro is a mall, which is located in the avenue." "Whose" is the possessive relative pronoun, used to indicate ownership or a relationship: "Laura, whose hair is red, is my student."