单选题 — Shall I get a birthday cake for Mary on my way back? —Yes, it'll be nice if you ______.
【正确答案】 A
【答案解析】[解题指要] 动词do有替代作用,以免重复。选项A=It will be nice if you get a birthday cake.do代替get a birthday cake。get是行为动词,不能用are代替。