Question: \section{
Language consists of three main parts. The first is simply vocabulary, the lexicon of words available to the speaker to describe particular concepts, actions, and states. The second part is morphology, the set of rules that dictates how words and parts of words may be combined to form other words. The final part of language is syntax, the rules that combine words into phrases and sentences. It is morphology that we shall turn our attention to first.
Morphology has two major subdivisions. They are derivation and inflection. Derivation refers to those rules by which new words may be formed out of preexisting words. Inflection, sometimes referred to as conjugation and declension, states how words are changed to indicate their function within a sentence.
Although common mythology holds that English is one of the most difficult languages to learn, many linguists would beg to differ. In fact, when it comes to inflection, 
the conditional, the subjunctive, the imperative, and others. Languages from outside the Indo-European family tree may be even more complex. The Bantu language of Kivunjo has roughly half a million combinations of prefixes and suffixes for a verb. English, however, has a mere four combinations. A verb such as to walk is limited to the following forms: walk, walks, walked, and walking.
Although there are only four basic verb forms, the English language does have more than 13 possible inflections. It just makes do with these four forms for the various functions. English also differs significantly from many other Indo-European languages in that in English, the stem of the word can be pronounced and is in fact part of the language. In Spanish, the stem of the verb to walk is camin-, but this is not a word in the language. In order to pronounce this word, it must be conjugated and combined with a suffix. English uses the stem form of the verb for four inflections: the present tense (except for the third-person singular), the infinitive, the imperative, and the subjunctive. The verb form ending in $-s$ is used in only one case, the third-person singular.
The two possible verb suffixes, -ing and $-e d$, are put to use in a variety of ways as well. The -ing ending appears in the progressive participle, the present participle, the gerund form, and the verbal adjective form. That leaves the $-e d$ form to handle the remaining inflections, including the past tense, the perfect participle, the passive participle, and some verbal adjectives.
Why are there so many different inflections for verb forms that basically sound the same? Simply put, the meanings implied by the various moods are different, even if the words used are fairly similar. Compare the meaning conveyed by the simple past tense (he walked) to the meaning inherent in the perfect participle (he has walked).
According to the passage, which English inflection can be expressed by two different verb suffixes?
I. the present tense
II. the verbal adjective
III. the present participle

Options:
A. I only
B. I and II only
C. III only
D. I, II, and III
Answer: This question asks about supporting details. The passage states that the present tense (statement I) is usually expressed using the stem form of the verb, but can also be expressed in the third-person singular by using the $-s$ suffix. Similarly, verbal adjectives (statement II) are sometimes expressed using the -ing suffix and sometimes with the -ed suffix. The correct answer is B.