一次风机RB动作结果是()。
A、投AB层大油;
B、跳同侧引风机;
C、跳同侧送风机;
D、协调退出。
参考答案:A, D
( ) 1. What do you want to do?( ) 2. Would you like to play ping- pong?( ) 3. How many pencils?( ) 4. What is it?( ) 5. Where is the picture?
分子式为C3H5Cl,且含C=C键的同分异构体有不考虑立体异构( )
A.2种
B.3种
C.4种
D.5种