完成下列句子（满分5分）

81.这本书对他的研究将有很大的价值。

This book will be      great       to him in his studies.

82.我们必须考虑到所有的事实。

We have to      all the facts into       

83.因缺乏交流而引发的家庭问题现在越来越多。

There are more and more family problems            the lack of communication.

84.该店由于正在修理屋顶，所以暂停营业。

The shop is closed        because the roof is         repair.

85.一些公司对女雇员有成见，认为女性不如男性能干。

Some companies are                    female employees and think that women are

not as capable as men.

风机启动前为何要关闭阀门？