A市某天的温差为7℃，如果这天的最高气温为5℃，这天的最低气温是______．
5-7=5+（-7）=-2℃．
故答案为：-2℃．
单词拼写。
1. Do you know where the _____ (源头) of the Mekong River is?
2. I have got two tickets for the evening _____ (表演).
3. Not having seen my friend for years, I could hardly r_____ him at first.
4. How much is the train _____ (费用) from Toronto to Montreal?
5. My sister is so s_____ that no one can persuade her into changing her mind.
在Java语言中，支持网络通信的软件所在的包是( )
A．java. util B．java. netC．java. io D．java. internet
