1 . （2021新课标II卷）A company representative wrote back and told me the airline was switching over ________ plastic to paper cups on all of its 1,200 daily flights. (用适当的词填空)

2 . （2022全国甲卷）He flew 4, 700 kilometers ________ Xi’an to Kashgar on Sept. 20. （用适当的词填空）

5 . It ran for just under seven kilometers and allowed people to avoid terrible crowds on the roads above as they travelled to and ________ work. (用适当的词填空)

6 . She managed to rescue the boy ________ the burning house. （用适当的词填空）

7 . He even received a medal ________ the Chinese government for his conservation efforts. (用适当的词填空)

8 . Customs vary ________ country to country, so you should learn to do as the Romans do. （用适当的词填空）

9 . The man ________ whom I received the letter was my best friend. (用适当的词填空)

10 . He is in hospital, recovering ________ a heart attack. (用适当的词填空)