人们常说“生命在于____”。
激光产生于____.
对aC2H2 +bO2 =m CO2 +n H2O中，系数之间关系正确的是（ ）
设集合A=x,y|x+y≤1，B=x,y|y-xy+x≤0，M=A∩B，若动点Px,y∈M，则x2+y-12的取值范围是（ ）
Picture
Description(描述)
____.
A. They're very smart. People kill them for their ivory.
____
B. Do you often watch him play basketball? If you do so, what do you think of him?
C. —I can't find my keys.
—Let me help you.
D. It's good exercise and also it's good for our environment (环境).
E. I always get up at 6 o'clock in the morning.
F．It means that you can't take photos.
俄国1861年改革是一场废除奴隶制的改革，它是俄国历史上的重大转折点，使俄国走上了资本主义发展的道路。
错误：____；订正：____。
