It's time to refresh your memory on subject-verb agreement (also called concord). Remember how both the subject and the verb have to be either singular or plural? If not, read about it in Key English at page 220 -221.
Take a look at the YouTube-clip above (click on this link if the video doesn't work). Then do task 22 and 23 at page 21 in Key English (remember to explain why you have chosen each verb in task 22 and make sure that you write complete sentences in both tasks, not just the verb you want to use).
9CD: This is homework for Monday September 1st.
9EF: This is homework for Thursday September 4th.