The real secret to successful learning lies in students＿＿＿＿an interest in what they are doing.

——How wise of you to come round，but why？
——______ that all is right.

You can hardly imagine the trouble the woman had______her children.

When I came in, I saw her sitting in the sofa ______ in thought.  

A small plane crashed into a hillside five miles east of the city, _________ all the four people on board.

In the lecture, little Tom kept silent all the time unless _________ to express his opinion.

___________ the man who lost the purse, Mike had to stay there longer.

___  an important decision more on emotion than on reason, you will regret it sooner or later.

If ____unsolved, the problem of food safety may lead to more serious results.

It’s reported that energy drinks are not allowed ___ in Australia.