禹州市“五城联创”活动如火如荼进行中，正在加强该市生态环境建设．以下措施对创建“五城”不合理的是（　　）

用括号内所给动词的适当形式填空。
____ In the past three years, my home town ______________(change) a lot. already.
____ It's hard to say what ____________ (happen) in 100 years in our country.
____ They_______________(not travel)to Shanghai next week, are they?
____ The students________(chat) from 6 to7 yesterday evening.
____ When I got to the station yesterday morning, my friends _______(wait ) for me at the entrance.
____ If it__________ (not rain) tomorrow, we'll go hiking.
____ He____________ (not write) a letter to his mother yet. He has to do that soon. His mother misses him very much.
____ Would you please__________(not make) such a big noise. The baby is sleeping.
____ It's a long time since we ________(meet) last time, isn't it?
____ ——How many times _______the girl __________(forget) to take the keys to her home?——At least three times.
____ You must spend as much time as you can ________  (practise) playing the piano.
____ They_______(live) in Wuxi since they were born.

在冬季晴朗的夜晚，山区低地往往会出现较严重的霜冻现象。山区易出现“霜打平地”现象的原因是夜晚（    ）

4－1=3

由3个亿， 5个百万， 2个千和8个十组成的数写作：____，读作：____。