请根据所给中文提示完成下列句子。

1. We should try our best to protect our __________ (环境) .

2. When you look up a word in the __________ (字典), pay attention to the first letter of the word.

3. I called you but __________ (没有人) answered the phone

4. We got much __________ (知识) of music from Mr.Lee last week.

5. Tony, you are always so ___________ (粗心的) .

B型后从板座侧面裂纹延及上平面或下平面时，焊修后在裂纹处下平面补（）补强板。

A.马蹄形

B.平形

C.角形