一束光线垂直射到平面镜上，入射角是______，反射角是______，当将平面镜转动15°时，入射光线与反射光线的夹角是______．

根据短文内容和首字母提示，在下文空格处填入适当的词使短文完整。在答题卡标有题号的横线上，写出空缺处各单词的正确形式。（每空一词）

Young people are often unhappy when they are with their parents. They say that their parents don’t u(66)      them. They often think their parents are too strict w (67)     them.

Parents often find it difficult to win their c (68)     trust, and they seem to forget how they themselves felt when they were young.

If you plan to do something, you’d better win your parents over and get them to understand you, if so, your parents will certainly let you do what you want to do.