下列对分子结构叙述不正确的是
A.H2O2分子中,两个O之间形成1对共用电子对 |
B.SiO2晶体中,1个Si原子与2个O原子形成两个共价键 |
C.有机化合物CH3—CH2—NO2和H2N—CH2—COOH是同分异构体 |
D.分子晶体溶于水时,分子中的化学键可能被破坏 |
What I need is_____ book that contains ______ABC of oil painting.
A.a; 不填 | B.the; 不填 | C.the; an | D.a ; the |
Jenny nearly missed the flight______ doing too much shopping.
A.as a result of | B.on top of | C.in front of | D.in need of |
The CDs are on sale! Buy one and you get ______ completely free.
A.other | B.others | C.one | D.ones ks |
I’m sure that your letter will get______ attention. They know you’re waiting for the reply.
A.continued | B.immediate | C.careful | D.general |
All the dishes in this menu, ______ otherwise stated, will serve two to three people.
A.as | B.if | C.though | D.unless |