A:甲硫醇(CH3SH)比甲醇的熔点低的原因是甲醇分子间易形成氢键
B:氯化钠易溶于水是因为形成了氢键
C:氨易液化与氨分子间存在氢键无关
D:H2O是一种非常稳定的化合物,这是由于氢键所致
There were __________ many horrible smells _______ I can't stay here more than one minute.
①-2mn+2nm=0;
②3x2+22x2=5x2;
③x2+2x2-5x2=-2x2;
④(-y)2+y2=0.
下列划线字注音完全正确的一项是( )
(____)⑴Open your mouth.
(____)⑵Touch your nose.
(____)⑶Stamp your foot.
(____)⑷Wave your arms.
(____)⑸Shake your legs.
A. B. C. D. E.
读下图,回答下列问题。