Let's play _______ volleyball.
play+球类/棋类/游戏名词。
句意：让我们打排球把。play volleyball是固定搭配，意为“打排球”，volleyball前不必加冠词，故答案为A。
—Did you call Michael back?
—I didn't need to,_____ I'll see him tomorrow.
考查连词的用法。
unless意为“除非”；because意为“因为”；when意为“当……时”；though意为“尽管”。根据本题语境可知，我不必给迈克回电话，“因为”我明天就要去见他了，because意为“因为”，表因果关系，符合本题语境。故选B。
—Would you like _______ a film with us tonight?
—Sorry,I have to help my mother do housework.
本题考查would like to do sth.的固定搭配。
问句的含义是“你今天晚上想和我们一起去看电影吗？”，would like to do sth.意为“想要做某事”，故答案为B。