Question

In which sentence does the verb number need to be changed in order to agree with the number of the subject?

Answer 1

Answer:

A. My aunt and uncle usually sends me a picture postcard when they travel.

Explanation:

The subject is My aunt and uncle. This phrase can be replaced with the pronoun they because we have two people here who send me a postcard. So  the verb number needs to be changed in order to agree with the number of the subject: it should be send, not sends.  

In other words, use a plural verb with two or more subjects when they are connected by and.