题目

Don't give up halfway, Andy. You'll succeed ________ if you keep on working like this. A . in return B . on time C . in time D . by accident 答案：C如果直角三角形的一条直角边长为6厘米，这条直角边所对的角是60°，则这个直角三角形斜边上的高为______厘米．