前牙中舌侧窝最深的牙是（）
A.上颌中切牙
B.上颌侧切牙
C.下颌侧切牙
D.上颌尖牙
E.下颌尖牙
参考答案：B
用所给词的适当形式填空。
1. Look! He is ________ (fight) with classmates.
2. Can’t you see it says, “No ________ (swim)”?
3. At home, she ________ (not have) to wear a uniform.
4. Arriving late for school ________ (make) the teacher angry.
5. Do you mind ________ (wash) hands here?
人体的生殖系统中既能产生生殖细胞又能分泌性激素的结构是
A．睾丸和子宫
B．睾丸和卵巢
C．输卵管和输精管
D．卵巢和附睾
