题目

It’s hard when a best friend isn’t around — maybe because he or she moved to a different school or a different class. 16_____ You want to have new friends, but how do you make them? Maybe it seems like everybody else already has his or her friends. 17____ Start by looking around your classroom — think about which kids you’d like to play with at break. Look for chances to say hi to them, smile, and be friendly. 18_____ Invite someone to play with you or say “Do you want to sit here?” in the lunchroom. When you’re at break, walk over to kids you want to play with, act fri某人以7m/s的速度走完全程的一半，后又以3m/s的速度走完剩下的一半路程，此人在全程中的平均速度为_________m/s 。