选择题:38.This disease ________ in Africa but has now spr

题目内容:
38.
This disease ________ in Africa but has now spread to many parts of the world. 
(A) derived
(B) originated
(C) sparkled
(D) dwelled
参考答案:

10、有两个调整压力分别为5MPa和10MPa的溢流阀串联在液压泵的出口,泵的出口压力为 ;并联在

10、有两个调整压力分别为5MPa和10MPa的溢流阀串联在液压泵的出口,泵的出口压力为 ;并联在液压泵的出口,泵的出口压力又为 。 ( )A

查看答案