根据句子结构的语法性，在下面空格处填入一个适当的词或使用括号中词的适当形式填空。
小题1:_________ (hear) their teacher's voice, the pupils stopped talking at once.
小题2:He _________ (bring) up in North Yorkshire by his grandmother .
小题3:It may be _________ (believe), but it's the truth.
小题4:She was so tired that she didn't even have the _________ (strong) to stand up.
小题5:She had her hair cut last night, now it is _________ (thin) and shorter.
小题6:Thousands of patients have benefited _________ the new medicine.
小题7:I find _________ strange that she doesn’t want to go.
小题8:Great changes _________ (take) place in China over the past few years.
小题9:Those _________ keep working hard will soon be successful.
小题10:We tried to save the building, _________ it was a hopeless task.
小题11:Please call me on your _________ (arrive) at the hotel.
小题12:She did not know _________ had happened.
小题13:With time _________ (go) by, my memory seemed to get worse.
小题14:I have borrowed _________ useful book from the library to prepare for my coming exam.
小题15:People began looking across to see_________ the noise was coming from.