1.         John is absent today. Because he is ill.

A. today. Because he is ill.

B. today because he is ill

C. today, because he is ill

D. today: because he is ill.

The correct answer is B. When used in the middle of a sentence, the word "because" should not be preceded by any punctuation. However, if you begin the sentence with "because", you need to use a comma: Because he is ill, John is absent today. Note that the grammatical classification of "because" is that of a subordinator.

2.         My apartment which is air conditioned, is cool in the summer.

A. apartment which is air conditioned,

B. apartment, which is air conditioned,

C. apartment, which is air conditioned

D. apartment which is air conditioned

The correct answer is B. In this sentence, the clause "which is air conditioned" provides extra, non-essential information about the speaker's apartment. When extra information is given in a sentence, commas must be used before and after the clause containing the information.

3.         John can run faster than me.

A. faster than me.

B. faster than I.

C. faster than myself.

D. faster, than I.

The correct answer is C. When comparing yourself to someone else by using the word "than," the word "than" must be followed by "I".

4.         Outrunning the other players on the football field, I saw Jack score the winning touchdown.

A.  field, I saw Jack score

B.  field, I saw Jack scoring

C.  field, Jack scored

D.  field, Jack scoring

The correct answer is C. The phrase "outrunning the other players on te football field" describes Jack. Therefore, the name "Jack" must come after this phrase. The past tense (scored) must be used because the action is completed at the time of speaking.

5.         When you pay with a stolen credit card, this is known as larceny.

A.  When you pay with a stolen credit card, this

B.  You pay with a stolen credit card, this

C.  Paying with a stolen credit card, this

D.  Paying with a stolen credit card

The correct answer is D. The words "paying with a stolen credit card" form the grammatical subject of this sentence. This type of -ing phrase is known as a gerund. Remember that gerunds look like verbs, but function like nouns. Since the gerund acts like a noun, it must be followed directly by a verb ("is").