题目内容
（请给出正确答案）
A.hard against
B.hard on
C.hard with
D.hard to
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更多“He is very ______ his children…”相关的问题
A.船长或船员的恶意行为或疏忽造成的损失，除保险单另有约定外，保险人不应负赔偿责任。
B.船长或船员的恶意行为或疏忽造成的损失，除保险单另有约定外，保险人应负赔偿责任。
C.船长或船员的恶意行为或疏忽，除保险单另有约定外，应视为保险人的行为。
D.在任何情况下，船长或船员的恶意行为或疏忽造成的损失，保险人应负赔偿责任。
_ on roofs and telegraph wires.These birds are swallows.They are __62__ together because, very soon, they will be flying __63__ to much warmer lands, where they will find __64__ the small flying insects on which they __65__.There are no such insects __66__ in Britain during the winter; it is __67__ cold for them.
The swallows settle, fly off, swoop, and __68__ again.this they do many times, for they are making short __69__ flights in order to be fit for the long journey __70__ them.
__71__ of these migrating birds leave Britain in the autumn.They fly __72__ for hundreds of miles __73__ they reach the warm lands of Africa.But not all the birds get there, for many of them perish in the stormy weather they meet with __74__.
In the spring of the following year they __75__ the long and tiring journey back to Britain.They return to the identical barn or tree in the __76__ district which they had left the __77__ autumn.How do these birds find their__78__ there and back over such vast distances？ Nobody knows exactly __79__, but it has something to do __80__ winds and air currents.
61.a.being perched b.perched c.being perching d.be perched
62.a.gathering b.assembling c.waiting d.forming
63.a.to south b.the south c.to southwards d.south
64.a.a great number of b.a great deal of c.plenty of d.numerous
65.a.feed b.are fed c.eat d.rely
66.a.near b.about c.nearby d.over
67.a.too b.a bit c.very d.much
68.a.fly off b.swoop c.settle d.turn back
69.a.practical b.practicing c.practice d.practiced
70.a.in advance b.ahead of c.in front of d.in front
71.a.Swarms b.Herds c.Flocks d.Schools
72.a.firmly b.stoutly c.harshly d.steadily
73.a.until b.before c.when d.as
74.a.in the way b.on the way c.half the way d.all the way
75.a.take b.fly c.find d.make
76.a.old b.original c.familiar d.identical
77.a.before b.previous c.above going d.former
78.a.way b.path c.course d.route
79.a.why b.when c.how d.what
80.a.against b.away c.for d.with
一氧化氮(NO)分子被美国《科学》杂志命名为1992年明星分子。在无机化学和生物无机化学中，NO是已得到深入研究的分子之一。
(1)写出基态的价电子组态，并回答下列问题：
(a)N原子和O原子间形成什么形式的化学键？
(b)键级多少？
(c)按原子共价半径估算N-O间的键长，并和实验测定值115pm比较。
(d)分子第一电离能比N2是高还是低？说明原因。比O2又如何？
(e)NO+键级是多少？估计其键长。
(D)NO+的伸缩振动波数比NO是大还是小？估计其数值.
(2)若忽略电子的轨道运动对磁矩的贡献，计算NO分子的磁矩。
(3)已知NO红外光谱的两个谱带的波数分别为1876.2cm-1和3724.6cm-1，计算第三泛音带的波数。
(4)NO紫外光电子能谱(HeⅡ线，40.8eV)的一部分示于图C.7.1中，图中的谱带对应于2
轨道。试解释此能谐分裂为两个谱带(分别对应于3Ⅱ和1Ⅱ态)的原因，并估算从2
轨道击出的光电子的最大动能。
(5)在腌肉时加入NaNO2，产生NO，NO与从蛋白质中解离出来的硫和铁结合生成[Fe4S3(NO)7]-，该离子有抑菌、防腐作用。X射线结构分析表明该离子的结构如图C.7.2所示，请指明该离子所属点群。
