精馏塔正常操作时,下列叙述正确的是()。
A.塔顶采出量等于进料量
B.塔进料量等于塔出料量
C.塔釜采出量等于进料量
D.塔釜采出量等于塔顶采出量
参考答案:B
Is this the reason____ at the meeting for his carelessness in his work?
A.he explained
B.what he explained
C.how he explained
D.why he explained
草坪害虫蝗虫类昆虫的前翅质地坚韧如皮革,其类型为()。
A.膜翅
B.鳞翅
C.半鞘翅
D.复翅