红蓝宝石的透明度较低、颜色较深时,宝石呈现的星光()。

题型:填空题

问题:

红蓝宝石的透明度较低、颜色较深时,宝石呈现的星光()。

考点:珠宝鉴定师珠宝鉴定师题库
题型:填空题

如下图所示,A、B、C三图依次表示在酶浓度一定时,反应速率和反应物浓度、温度、pH的关系。请据图回答下列问题。

(1)图A中,当反应物达到某一浓度时,反应速率不再上升,其原因是____。

(2)图B中,a点所对应的温度称___________。

(3)图B中,a点到b点的曲线急剧下降,其原因是______________________。

(4)将装有酶与反应物的甲、乙两试管分别放人12℃和75℃的水浴锅中,20min后取出,转入37℃的水浴锅中保温,两试管内的反应分别为:甲_________,乙________。

(5)图C表示了___________催化反应的速率变化曲线。

A.唾液淀粉酶 B.胃蛋白酶 C.胰蛋白酶 D.植物淀粉酶

题型:填空题

“Can I see my baby?” asked the happy new mother. The bundle (a collection of things wrapped or boxed together) was placed in her arms and when she moved the fold of cloth to look upon his tiny face, she gasped -- the baby had been born without ears. Time, however, proved that the baby’s hearing was perfect except his appearance.

One day when he rushed home from school and threw himself into his mother’s arms, he cried out bitterly, “A boy, a big boy… called me -- a f... freak.” She sighed, knowing that his life was to be endless of heartbreaks.

He grew up, handsome for his misfortune. A favorite with his fellow students, he might have been class president, but for that. He developed a gift for literature and music.

The boy’s father had a talk with the family doctor. Could nothing be done? “I believe we could graft (移植) on a pair of outer ears, if they could be donated (捐献) ,” the doctor decided. So the search began for a person who would make such a sacrifice for a young man. Two years went by. Then, “You’re going to the hospital, son. Mother and I have someone who will donate the ears you need. But it’s a secret.” said the father.

The operation was a brilliant success. His talents blossomed into genius. School and college became a series of successes. Later he married and entered the diplomatic (外交) service. “But I must know!” he urged his father. “Who gave so much for me? I could never do enough for him.”

“I do not believe you could,” said the father,“but the agreement was that you are not to know…not yet.” The years kept the secret, but the day did come... one of the darkest days that ever passed through a son. He stood with his father over his mother’s casket (棺材). Slowly and tenderly, the father stretched forth a hand and raised the thick, reddish-brown hair to let out the secret.

小题1:The story is mainly about _______.

A.how a boy had new ears through an operation

B.what a devoted parent privately did for the child

C.how a disabled boy turned into a useful person

D.why a donator made a sacrifice to a bright boy小题2:From the first paragraph we know that the mother _______.

A.was determined to donate her ears to perfect her son

B.kept her husband unknown about the baby’s situation

C.felt shocked and disappointed to see her new baby

D.complained of her bad luck to have a disabled child小题3:The underlined word “freak” in Paragraph 2 is the closest in meaning to “_______”.

A.slow-acting person

B.funny-looking child

C.badly-behaved student

D.strangely-shaped creature小题4:What can be inferred from the passage?

A.The agreement was between the donator and the family.

B.The boy was so popular that he was made class president.

C.Finally the boy came to know who the donator was.

D.The mother donated her ears to her son after she died.小题5:What moral lesson can we draw from this reading?

A.Real love lies in what is done unknown rather than what is done known.

B.It is parents’ responsibility to help their children heart and soul.

C.True beauty lies only in the heart not in appearance.

D.Young generations should learn to be grateful.

题型:填空题

在汽车万向传动装置中,当主动轴转动时,从动轴既能随之转动,又可绕十字轴中心在()方向摆动。

A.上下

B.左右

C.任意

D.向左

题型:填空题

春秋战国时期的私人秘书称为什么?

题型:填空题

不能在M-H琼脂上生长良好的细菌是()

A.肺炎链球菌

B.金黄色葡萄球菌

C.肺炎克雷伯菌

D.大肠埃希菌

E.以上都不是

更多题库