Nobody can bear __________ at in public places.
We cannot figure out _______ quite a number of insects, birds, and animals are dying out.
Is this the reason _______ at the meeting for his carelessness in his work?
_______ puzzles me most is that I don’t know _______ the difference between those two lies.
In our classroom, the pupils work in groups, _______ helps them to learn to co-operate, to share and to develop leadership skill.
We agreed to accept _______ they thought was the best professor in the college.