外伤性房角后退继发性青光眼常发生于
A．伤后数周或数年
B．伤后数周
C．伤后数日
D．伤后1周内
参考答案：A
The boy _____ so much time on the computer games that he didn’t have enough time to study. [ ]
A. cost
B. spent
C. paid
D. took
物体的重力是地球对它的（）。
A、主动力
B、吸引力
C、平衡力
