一条彩带长3.6米，对折三次，平均每段长多少米？
3.6÷（2×2×2）
=3.6÷8，
=0.45（米）．
答：平均每段长0.45米．
He must be helping the old man to water the flowers,______
A. is he B. isn't he C. must he D. mustn't he
39. A huge forest fire ______ after the lightning struck, but luckily no one died or got hurt.
A．broke out
B．broke up
C．broke down
D．broke off
