外存储器的特点为______.
A、可靠性高、每字节价格低
B、机械结构复杂
C、存储速度慢
D、存储容量大

A．Look for examples when they are reading and doing research about the ideas that they are going to present in their papers.
B．Copy the good sentences when they are reading and doing research about the ideas that they are going to present in their paper.
C．Recite the grammar rules on the grammar book.
D．Summarize the grammar rules of the papers they’ve read.