The workers in the Huashan Mountains have to rubbish to keep the mountains clean.
A. turn up
B. pick up
C. mix up
D. give up
网友回答
A. turn up
(答案→)B. pick up
C. mix up
D. give up
解析：难度适中，考查词组的意思，turn up出现，发生，pick up拾起，收拾mix up混淆，弄混，give up放弃，答案选的应该是B。