下列实验方法错误的是 （ ）
| A．用水鉴别硝酸铵固体和氢氧化钠固体 |
| B．用紫色石蕊溶液鉴别二氧化碳气体和一氧化碳气体 |
| C．用稀盐酸除去氯化钠溶液中混有的少量碳酸钠 |
| D．用稀盐酸除去铁粉中混有的少量镁粉 |
Thousands of houses _______ by the floods in Guangxi last month.
| A． | destroy | B． | destroyed | C． | have destroyed | D． | were destroyed |
more, and you'll improve your spoken English.
| A． | Speak | B． | Speaks | C． | Speaking | D． | To speak |
--- I've just got a postcard from my pen friend.
--- Let me have a look
. Wow.nice card!
| A． | What | B． | What a | C． | How | D． | Why |
--- What is your favourite sport?
--- Swimming, I think. It's of all.
| A． | earsier | B． | more difficult | C． | the most interesting | D． | the most boring |
---I use your ruler, Lingling?
--- Sure. Here you are.
| A． | May | B． | Would | C． | Need | D． | Must |