简述使用浓盐酸有哪些好处？

甲旅行社由于某饭店不能提供客房而对旅游者造成违约，（）应当向旅游者承担违约责任。

A．甲旅行社

B．某饭店

C．甲旅行社和某饭店

D．甲旅行社或某饭店

阅读理解。

     A sense of humor is just one of the many things shared by Alfred and Anthony Melillo, 64-year-old twin

brothers from East Haven who made history in February 2002. On Christmas Eve, 1992, Anthony had a heart

transplant from a 21-year-old donor. Two days before Valentine's Day in 2002, Alfred received a 19-year-ok

heart, marking the first time on record that twin adults each received heart transplants.

     "I'm 15 minutes older than him, but now I'm younger because of my heart and I'm not going to respect

him," Alfred said with a grin, pointing to his brother while talking to a roomful of reporters. who laughed

frequently at their jokes.

     While the twins knew that genetics might have played a role in their condition,they recognized that their

eating habits might have also contributed to their heart problems. "We'd put half a pound of butter on a steak. 

I overdid it on all the food that tasted good, so guess I deserved what I got for not dieting properly."

     The discussion moved to Anthony's recovery. In the five years since his heart transplant, he had been on

an exercise program where he regularly rode a bicycle for five miles, swam each day, and walked a couple

of miles. He was still on medication, but not nearly as much as Alfred, who was just in the early stage of his

recovery.

     "Right now I feel pretty young and I'm doing very well," Anthony said. "I feel like a new person."

     Alfred said his goal, of course, was to feel even better than his brother. But, he added, "I love my brother

very much. We're very close and I'm sure we'll do just fine."

1. This article is mainly about _____.

A. the danger of heart transplant surgery

B. becoming young by getting a new heart

C. the effect of' genetics on the heart

D. the twin brothers who received heart transplants

2. What did Alfred and Anthony have in common?

A. Lifespan. 

B. Career goals.

C. A sense of humor.

D. Love for bicycling.

3. What did Alfred and Anthony think caused their heart problems?

A. Exercise.

B. Diet.

C. Surgery.

D. Medicines.

4. Why did Alfred say, "I'm 15 minutes older than him, but now I'm younger because of my heart"? 

A. His heart transplant surgery was more successful than Anthony's.

B. His recovery from the heart surgery was faster than Anthony's.

C. His exercise program was better than Anthony's.

D. His new heart was younger than Anthony's.

B－DNA代表细内DNA的基本构象，在某些情况下，还会呈现A型，Z型和三股螺旋的局部构象。

压缩机的出口气温过高是什么原因？

流速式水表按其适用的水温范围可分为冷水表和热水表，热水表的水温一般不超过( )。

A．40℃
B．50℃
C．80℃
D．90℃