神经肌肉接头后膜上受体的β蛋白亚基的分子量为（）
A.40000
B.50000
C.60000
D.65000
E.80000
参考答案：B
根据含义提示完成句子。
1. One of my classmates is going to be a policeman when he _____ _____ (长大).
2. I'd be very _____ _____ _____ (非常想听听) your opinion.
3. In those days, people all _____ _____ _____ (过着艰苦的干活).
4. Lots of people are _____ _____ (做兼职工作) jobs now.
5. Our purpose is to do _____ (更多) things but use _____ (较少) time.
为什么说五四运动是中国新民主主义革命的伟大开端
