问题 选择题

将100g25%的硝酸钾溶液稀释,取10g稀释后的溶液,经测定得知其溶质质量分数为10%,则稀释时所用水的质量是(  )

A.50g

B.100g

C.150g

D.200g

答案

因为取10g稀释后的溶液其溶质质量分数为10%,所以稀释后所有溶液溶质质量分数均是10%,则有需加水的质量是x

100g×25%
100g+x
×100%=10%,解得x=150g

故选C

阅读理解

More than seven hundred years ago, the Prince(王子)of Wales had a very big and brave dog called Gelert.

One day the Prince wanted to go hunting with his men. He told his dog to stay at home and look after his baby son. The baby was in a small wooden bed.

When the Prince came back from hunting, Gelert ran out to meet him. He wagged his tail and jumped up to put his paws on the Prince's chest. Then the Prince saw the blood on his head. He rushed into his house and found the bed lying on its side on the floor. The clothes were torn and there was blood on them.

The prince thought the dog had killed his son and took out his sword, killing the dog. Just as Gelert was dying, he managed to bark. Then the Prince heard a baby call to the dog. The Prince ran out of the house and saw his son lying on the ground unhurt. Near him was a dead wolf.

The Prince ran back into the house but it was too late. Gelert was dead. The Prince was very sad indeed. Tears ran down his face when he realized he had killed his faithful friend. The Prince carried the body of his brave dog to the top of a mountain and buried him there. After this, the Prince never smiled again.

If you go to Mount Snowdon in Wales, people will show you where Gelert is buried. There is a sign by his grave. It reminds people of a brave and faithful dog.

小题1: The Prince told the dog to            when he was leaving.

A.watch the door

B.take care of his baby at home

C.welcome his friends

D.stop the strangers小题2:. The dog was very           when his master came back from hunting.

A.glad

B.sorry

C.afraid

D.upset小题3:. The underlined word “faithful” in Paragraph 5 most probably means           .

A.友好的

B.温顺的

C.忠诚的

D.聪明的小题4: The Prince never smiled again because           .

A.the wolf was killed by Gelert

B.he had buried the dog on the top of mountain

C.Gelert had killed his baby son

D.he had killed his faithful friend Gelert

判断题