A:to prevent; being polluted
B:preventing; polluting
C:preventing; being polluted
D:to prevent; polluting
要使分式x+2x-1有意义,则x的取值应满足( )
人体内肺泡与血液的气体交换后,肺泡中( )
yíng
____养 热泪____眶 ____合 输____
kěn
中____ ____老玉米 诚____ ____荒
She says that she'll have to close the shop _______ business improves.
有人认为,十月革命是一场人为的“强制性”爆发的革命。下列能够作为这个结论依据的是( )