2 . ______ caused the accident remains unknown. (用适当的词填空)

3 . Your lights will come on the ________ (一……就) you enter the door along with your favorite music and TV programmes. (根据汉语提示单词拼写)

4 . In the beginning, Tu Youyou went to Hainan, _______malaria was more common, to study malaria patients. (用适当的词填空)

5 . Circumstances changed in 1933, _______ Hitler came to power in Germany. (用适当的词填空)

6 . My health monitor, _______ I wear all the time, has also helped me get into the best shape of my life. (用适当的词填空)

7 . 我仍然记得我们的第一次见面，似乎发生在昨天一样。
I can remember our first meeting ________ ________ it were yesterday.

8 . Written Chinese has also become an important ________ ________ ________ China’s present is connected with its past. (定语从句)
汉字书写也成为连接中国的过去与现在的一种重要手段。

9 . There was a time _________, if a lady got onto a crowded bus or train, a gentleman would stand up and offer her his seat.

A．while

B．as

C．when

D．until

10 . In August, radioactive wastewater from Japan was released into the Pacific Ocean, _________ effects people are still suffering.

A．by which

B．from which

C．from whose

D．by whose