先通读下面的短文，然后根据短文内容和所给首字母，在空格内填入一个适当的词，使短文意思完整。
   M____  friends is a skill like other skills. It improves with practice. If you want to meet people and make friends, you must be willing to take some a____ .
   You must first go where there are many people. You won’t make friends staying at home. Join a club or a party, talking with those who like the s____   things as you do. Or join someone in some a____.
   It’s human nature to feel a bit u____  about the unknown. Most of our fears come from doubts about o____ . Don’t forget they must be feeling the same way. Try to accept yourself as you are, and try to put the other person at ease（自由自在）. You’ll b____  feel comfortable.
   Try to act self-confidently t____  you don’t feel that way. When you enter a room    f____  of strangers, walk tall and straight, look directly at them and smile. Meeting someone new doesn’t mean that you will make friends because friendship is based on mutual liking（基于互相喜欢） and “give and take”. It takes t____  to develop.

读某地热力环流示意图（a、b表示等压面），回答下题．

小丽想探究活细胞的膜透性，她将兔子的红细胞放到清水中，一段时间后(t)，用显微镜观察，发现红细胞膨胀，体积明显增加，如下图所示。从实验结果可知

如图，直线y=-$\frac{4}{3}$x+4与x轴，y轴分别交于A，B两点，把△AOB绕点A顺时针旋转90°后得到△AO′B′，则点B′的坐标是(   )