问题 填空题

等腰三角形的一条腰上的高线等于该三角形某一条边的长度的一半,则其顶角的度数等于______度,______度,______度.

答案

此题首先要分两种情况讨论:

①当等腰三角形的顶角是钝角时,一条腰上的高在外部,当该高是腰的一半时,则与其顶角相邻的外角是30°,故顶角是150°;当该高是底边的一半时,其底角是30°,故顶角是180°-30°×2=120°;

②当等腰三角形的顶角是锐角时,一条腰上的高在内部.当该高是底边的一半时,底角是30°,顶角仍然是120°;当该高是腰的一半时,顶角是30°.

综上所述,有三种情况:30°,120°,150°.

故填30,120,150.

完形填空

第二节: 完形填空(共20小题, 每小题1.5分,满分30分)

请认真阅读下面短文,从短文后各题所给的A、B、C、D四个选项中,选出最佳选项,并在答题卡上将该项涂黑。

One day a king and his minister(大臣)went out for a walk. The king said to the minister, “I want to give reward to anyone who is hospitable(好客的) to us during our   21   .”

The king and the minister went up to one man and said, “We are   22    . This is a fine town. Could we stay at your house as   23    ?”

The man looked down upon them, saying, “  24  do I know you’re not criminals?”

Then the king and the minister went up and   25   on somebody else’s door. When the man opened the   26   , they asked, “Could we spend the night here? It’s getting dark.”

The man said, “First, tell me   27  of you there are. Then I’ll decide.”

The king said, “You see that we are only two. If you   28   us to stay with you, we’ll pay you what we have tomorrow.” The man agreed.

Then they   29   walking. They came to another house and knocked on the door. The king said, “It’s getting dark.   30  we spend the night at your house?”

The man said, “   31   ! Just tell me how many of you there are.”

The king said, “You can see we are only two.” Then they   32   back to the palace.

The minister had  33    the address of each person to whom they had spoken, and the following  34  the king called all the three persons to the palace. To the first one the king said, “When travelers come from a different kingdom, we must  35  them shelter(住所). It is   36    we aren’t thieves.” And the king   37  the man out of his kingdom.

To the   38 man the king gave a lot of money. To the third one, who  39    offered shelter and only then asked how many were in their party, the king gave his  40  .

21.   A sleep            B talk      C dinner        D walk

22.   A friends B criminals     C ministers     D travelers

23.   A owners B officials      C officers       D guests

24.   A How    B Why    C When   D Where

25.   A dropped      B took     C knocked      D touched

26.   A letter    B box      C door    D window

27.   A how many   B how much C how long    D how far

28.   A .agree       B allow   C make   D want

29.   A began   B enjoyed       C stopped       D continued

30.   A Would           B Must    C Could  D Should

31.   A Pardon B Thanks       C Sorry   D Certainly

32.   A went  B hurried       C returned     D drove

33.   A taken away  B taken down        C taken off    D taken up

34.   A year     B month  C minute D day

35.   A borrow B offer   C lend    D share

36.   A silly     B right  C clean   D clear

37.   A threw   B invited       C kept    D brought

38.   A last     B first     C third    D second

39.   A bravely       B slowly           C immediately       D carefully

40.   A order   B promise      C name   D crown

单项选择题