120-1阀应该既能适应在（）下运用，又能在没有压力保持条件下与GK阀、120阀混编使用。
参考答案：压力保持条件下
我国玉米划分成那几个区？
We agree to accept _____ they thought was the best tourist guide. [ ]
A. whichever
B. whoever
C. whatever
D. whomever
