We must ___ that the experiment is controlled as rigidly as possible.

The sales manager had his secretary _____ a press conference for their new products.

Susan is always a shy girl and feels ______in the presence of strangers.

The Blacks are _____ people in the little town.

这道题这么复杂，我们要用很多时间才能解决。

When he arrived in that country, he found that there is little occasion to speak Chinese.

This is the very house____my grandpa lived before his death in 2010.

You're going to England next year. You should now practice _____ English as much as possible.

75.（）

71.（）

According to Mrs. Brown, the purpose of teaching her children at home is （ ）.

这个漂亮干净的城市给外国旅游者留下了深刻的印象。