1 . Many lessons are now available online, from ___________students can choose for free. (用适当的词填空)

2 . The books on the desk, of ________ the covers are shiny, are prizes for us.

3 . In the 2018 FIFA World Cup, South Korea beat German, the last World Cup champion, ________ was unexpected.

4 . She has two sons, both of________are doctors. (用适当的词填空)

5 . _________is known to all, China is a developing country. (用适当的词填空)

6 . John invited about 40 people to his wedding, most of ________ were family members. (用适当的词填空)

7 . She brought her three friends to the party, none of ________I had ever met before. (用适当的词填空)

8 . The science of medicine, _________which we owe a great deal, is perhaps the most important of all the branches of science. (用适当的词填空)

9 . 这产生了连锁反应，使生命得以发展。
This produced a________ ________,________ ________it possible for life to develop.

10 . Yuan Longping, slim and strong, looks like millions of farmers________he has struggled for the past six decades.

A．for whom

B．to whom

C．who

D．for those