问题

decided to concentrate all my efforts _____ the complicated problem.

A: to solve
B: to be solved
C: on solving
D: in solving

正确答案是：

同类题型

B【解析】试题分析：考查动词辨析：

a, the summer vacation is approaching. How shall I do my travel-It’s your money, your time-spend it how you want.＿＿＿

“Do you mind if I look at your notes”—“Of course not _______”

下列句子中加点词的用法不相同的一项是（）

December is the __________ month in year