计算:(279)12+(0.125)0-(3)9÷(3)7.

题型:解答题

问题:

计算:(2
7
9
)
1
2
+(0.125)0-(
3
)9÷(
3
)7
考点:有理数的乘方零指数幂(负指数幂和指数为1)实数的运算
题型:解答题

下列关于钠原子和钠离子的说法中,正确的是

A.它们的核外电子数相同

B.它们的性质完全相同

C.钠原子的质量比钠离子大的多

D.它们的质子数和中子数都相同

题型:解答题

Although I often send e-mails to Tom, I have never seen him _____. [ ]

A. eye to eye

B. face to face

C. with eyes

D. on my own

题型:解答题
One afternoon in January in 1998, Susan Sharp, 43, and her 8-year-old son David, were walking across an icy square, when Susan’s cane(手杖) slipped on the ice. Her face   36  first into the mud. David   37  her mother’s side, “Are you all right, Mom”  38 , Susan pulled herself up, “I’m okay, Honey,” she said.
Susan was falling more   39  since she had trouble walking. Every inch of ice was a   40  danger for her. “I wish I could do something,” the boy thought. David, too, was having   41  of his own. The boy had a speech problem, so at school he talked   42 .
  One day, David’s teacher announced a   43  homework. "Each of you is going to come up with an   44 ," she said. This was for "INVENT AMERICA", a national competition to encourage creativity in children.
  An idea   45  David one evening. If only his mother’s cane didn’t slip on the ice. “What if I   46  your cane to a nail coming out of the bottom” he asked his mother.
  “  47  the sharp end would scratch(划破) floors,” Susan said.
  “No, Mom, I   48  make it like a ball-point pen. You take your hand off the button and the   49  returns back up.” Hours later the cane was finished. David and his father   50  as Susan used it to walk 50 feet about the   51 . Happily Susan cried out, “It   52  !”
  In July 1999, David was  53  national winner for the "INVENT AMERICA". David began to make public appearance. Thus he was forced to communicate  54 .Today, David is nearly free of his speech problem, and his   55  is becoming well accepted.
1. A. fell
B. touched
C. lay
D. dropped
2. A. stood by
B. rushed to
C. looked at
D. ran around
3. A. Firmly
B. Easily
C. Quickly
D. Shakily
4. A. slowly
B. frequently
C. freely
D. heavily
5. A. hiding
B. certainly
C. possible
D. waiting
6. A. method
B. disease
C. trouble
D. hope
7. A. few
B. little
C. much
D. more
8. A. useful
B. strange
C. common
D. special
9. A. appearance
B. invention
C. experience
D. experiment
10. A. reminded
B. encouraged
C. occurred
D. hit
11. A. fastened
B. stuck
C. fixed
D. tied
12. A. So
B. And
C. For
D. But
13. A. might
B. would
C. did
D. need
14. A. pen
B. hand
C. cane
D. nail
15. A. watched
B. supported
C. noticed
D. helped
16. A. street
B. ice
C. yard
D. square
17. A. works
B. operates
C. succeeds
D. helps
18. A. declared
B. received
C. won
D. praised
19. A. more slowly
B. more carefully
C. more clearly
D. faster
20. A. cane
B. mother
C. speech
D. story
 
题型:解答题

电子商务利用电子化的手段 ,尤其是利用互联网技术来完成物流全过程的协调、控制和管理,实现从网络前端到最终客户端的所有中间过程服务。

题型:解答题

结合家禽的解剖特点,试述家禽抗病能力差的原因。

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