根据句意完成已给出首字母或汉语提示的单词，使补全后的句子意思通顺、语法正确。

1. Tom and Sam are twins, but there are some d_____ between them．

2. Hawaii is f_____ for its beautiful beaches．

3. Our math teacher is a s_____ man．It seems that he never laughs．

4. Chinese medicine is now popular in many w_____ countries．

5. You can call Miss Zhang for more _____(信息)．

6. Your vacation _____ (计划) sounds wonderful．

7. My eating  _____  (习惯) is pretty good．

8. Lots of _____ (游客) come to Qingdao every day．

投用换热器时引入热介质操作中应首先（）。

A、稍开热介质出口阀

B、全开热介质入口阀

C、稍开热介质入口阀

D、全开热介质入口阀