【简答题】Rewrite the following sentences on the basis of general principles of business letter-writing : We request the favour of a reply at your earliest convenience.
【判断题】气相色谱和液相色谱是根据固定相的状态来分类的。
【判断题】气相色谱法和液相色谱法是根据流动相的不同分类的
【简答题】Task 4 Rewrite the following sentences after the models. (Model 2) 1. You will go past the post office. Will you drop the letter in the post box? 2. I was doing my homework. My father was watching TV...