-- Please help me, will you?
-- _________.
A:You’re welcome
B:Of course, I will.
C:Not at all
D:It’s my pleasure
下列计算: ①3a+2b=5ab; ②5y2—2y2=3; ③7a+a=7a2; ④4x2y-2xy2=2xy.其中正确的有( )
植物通过光合作用为人类提供( )
The man stopped smoking because of lung cancer.