题目

题型：不详难度：来源：

(2013·成都一诊)Parents are doing all they ________ to help their children achieve their ambitions.

A．shall	B．can
C．may	D．need

答案

B

解析

选B　考查情态动词。句意：父母们在做他们力所能及的事来帮助他们的孩子实现他们的夙愿。完整形式为“Parents are doing all they can do to help their children achieve their ambitions.”其中they can do是定语从句，修饰先行词all; to help  their children achieve their ambitions是目的状语。由于主句中出现了实义动词doing，所以省略了从句中的do。故答案为B。