A:6
B:8
C:10
D:12
The man in black must be Lily's brother.(改为否定句)
The man in black ____ ____ Lily's brother.
We go to ______ at six thirty in the morning.
shān hóng
měng zhǎng
lǎn duò
sú yǔ
____
①“x2+x﹣2>0”是“x>1”的充分不必要条件
②命题:“∀x∈R,sinx≤1”的否定是“∃x0∈R,sinx0>1”.
③“若x= π4 ,则tanx=1,”的逆命题为真命题;
④若f(x)是R上的奇函数,则f(log32)+f(log23)=0.
在“验证玻意耳定律”的实验中,下列操作正确的是()