已知25x2-36=0，y3+8=0，则x+y的值是______．

阅读理解。

     Tom was a clever boy, but his parents were poor, so he had to work in his spare time and during his

holidays to pay for his education. In spite of this, he managed to get to the university, but it was so

expensive to study there that during the holiday he found it necessary to get two jobs at the same time so

as to make enough money to pay for his studies.

     One summer he managed to get a job in a butcher's shop(肉店) during the day-time, and another in a

hospital at night. In the shop, he learnt to cut meat quite nicely, so the butcher often left him to do all the

serving while he went to the back room to do the accounts(账目). In the hospital , on the other hand, he

was , of course , allowed to do the simplist jobs, like helping to lift people and to carry them from one

part of the hospital to another. Both at the butcher's shop and at the hospital, Tom had to wear white

clothes.

     One evening at the hospital, Tom had to carry a woman from her bed to the place where she was to

have an operation. The woman was already feeling frightened at the thought of the operation before he

came to get her, but when she saw Tom, that finished her.

     "No! No!" she cried. "Not my butcher! I won't be operated on by my butcher!" and fainted away

(昏厥).

1. Tom made enough money by ________.

A. studying in the university            

B. working in a butcher's shop

C. doing two jobs                    

D. cutting meat well

2. Tom was a student, but at the same time he was__________.

A. a butcher and a doctor              

B. a manager and a doctor

C. an assistant                        

D. a manager

3. The woman patient recognized Tom because ____________.

A. he was wearing white clothes          

B. he had sold meat to her

C. he was now working in the hospital    

D. he was going to operate on her

4. When she saw Tom, that finished her, because the sight of Tom _________.

A. plunged(使进入) her into deep sorrow  

B. made her decide not to have an operation

C. broke her heart                      

D. took all her strength and courage away

板平面方向性系数？

我国境内公司发行的，在香港上市的股票是( )

A．B股

B．H股

C．N股

D．S股

艾滋病暴露源的病毒载量水平分为轻度、重度和暴露源不明三种类型，以下属于轻度的是（）。

A.经检验，暴露源为艾滋病病毒阳性，但滴度低、艾滋病病毒感染者无临床症状、C.D.4计数正常者。

B.经检验，暴露源为艾滋病病毒阳性，但滴度高、艾滋病病毒感染者有临床症状、C.D.4计数低者。

C.不能确定暴露源是否为艾滋病病毒阳性者。

D.上述都不对。

在氧化还原滴定法中，常根据所用的（）不同而将此法分为高锰酸钾法、重铬酸钾法、碘量法、溴酸钾法等。

A.还原剂

B.氧化剂

C.指示剂

D.滴定剂