原式=(34+712-56)×(-60),
=-34×60-712×60+56×60,
=-45-35+50,
=-30.
读句子,选择正确的图片,将其序号填入题前括号里。
( ) 1. Put on your sunglasses.
( ) 2. Take your raincoat.
( ) 3. Hold on to your hat.
( ) 4. Put on your boots.
( ) 5. Open up your umbrella.
A. B. C. D. E.
简述论辩的基本原则和要求?