We must try our best to keep the _____of_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题选择题

We must try our best to keep the _____ of nature. [ ]

A. balance

B. balanced

C. balancing

D. balances

答案

答案：A

问答题

内流河：______（我国最长的内流河）．

填空题

立磨的入磨回转下料器主要起（）作用。