列竖式计算并验算.
564÷47
840÷12.
564÷47=12;
840÷12=70.
He is a man of few words, and seldom speaks until _______ to.
A.spoken
B.speaking
C.speak
D.be spoken
砒霜不能配用的是()
A.川乌
B.芒硝
C.官桂
D.人参
E.水银