二尖瓣位于（）
A.上腔静脉口
B.下腔静脉口
C.主动脉口
D.肺动脉口
E.以上都不对
参考答案：E
看图写单词，将句子补充完整。
1. It's a day. She doesn't have her and . She is .
2. Some are at the .
3. — How are you? — I am years old.
4. — What's the temperature? — It's degrees.
1. 2. 3. 4.
The policeman asked him when the accident happened. [ ]
A. what was he doing
B. what did he do
C. what he was doing
D. what he did
2. 
3. 
4. 