(1)原式=23-2-(3- 2)
=23-2-3+2
=3;
(2)原式=0.8×52×2=4.
按正确的顺序排序。
A. I want to take a picture! May I have your camera?
B. It's about five hundred years old.
C. Sure. May I help you take a picture?
D. How old is the Palace Museum, Li Ming?
E. That's old.
F. No. thanks! Cameras are easy.
正确的顺序: _________________________________________
把一根直木杆一端系细绳长1.Om,绳端系一垂球,将杆平放于地面并伸出一定长度,使垂球触于坡面,若量得木杆伸出的长度为(),则坡度为1:2。
A.4m
B.2m
C.3m
D.1m