根据句意及其首字母提示补全单词。（10分）

小题1:We think the best way to relax is t        exercise.

小题2:She n        goes to learn swing dance because he dislikes it.

小题3:My mother told me a good friend is like a m        .

小题4:He still went to school on time t        he didn’t feel well yesterday.

小题5:He was so funny that  he often makes his friends l        .

小题6:Parents play a r       in their children’s lives.

小题7:The supermarket(超市) is always c        on weekends.

小题8:Liu Qian is a popular m         from Taiwan.

小题9:It’s n       for us students to finish homework on time.

小题10:My maths teacher is very s       . He never laughs in class.

专有技术的特征除了经济性、可传授性和历史性外，还有一个重要特征是（）。

A.保密性

B.时效性

C.有效性