眼的光学常数包括有()。
A.角膜,房水、晶状体、玻璃体
B.主点、结点、焦点
C.折射率、曲率半径、厚度
D.屈光介质、屈光力
参考答案:C
_______ seems strange to us is ______ the troublesome boy is getting along well with all his teachers. [ ]
A. It; that
B. What; how
C. It; how
D. What; that
花木选择应用中,红色夏花类乔木有()、()。