成煤作用_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题名词解释

成煤作用

答案

参考答案：

从植物遗体的堆积到形成煤层的转化过程，称为成煤作用

选择题

— How many times have you been to China?
— In fact, it is the first time I _____ here.

A. was
B. am
C. had been
D. have been

判断题

在锌片与铜片相连形成的原电池中，锌片是负极，铜片是正极。