Theemployeeswereaskedtoconcentratetheirattention

问题详情：

The employees were asked to concentrate their attention________improving the quality of the products.

A．in                                                      B．to   

C．with                                                   D．on

【回答】

D　考查固定短语。concentrate one’s attention on doing sth.意为“集中精力做某事”。

知识点：介词

题型：选择题