下列不屈于制备脂质体的方法是A．注入法 B．薄膜分散法 C．逆相蒸发法 D．超声波分

阅读理解。

     A friend of mine named Paul received an expensive car from his brother as a Christmas present. On

Christmas Eve when Paul came out of his office, a street urchin (顽童) was walking around the shining

car. “Is this your car, Paul?"he asked.

     Paul answered, "Yes，my brother gave it to me for Christmas. "The boy was surprised. "You mean

your brother gave it to you and it didn't cost you anything?Boy, I wish…”He hesitated.

     Of course Paul knew what he was going to wish for. He was going to wish he had a brother like that.

But what the boy said surprised Paul greatly?

    "I wish, "the boy went on, "that I could be a brother like that. "Paul looked at the boy in surprise，then he said again, "Would you like to take a ride in my car?"

     "Oh yes, I'd love that. "

     After a short ride，the boy turned and with his eyes shining, said, "Paul, would you mind driving in

front of my house?"

     Paul smiled a little. He thought he knew what the boy wanted. He wanted to show" his neighbours that he could ride home in a big car. But Paul was wrong again. "Will you stop where those two steps are?"

the boy asked.

     He ran up to the steps. Then in a short while Paul heard him coming back, but he was not coming fast. He was carrying his little crippled(残疾)brother. He sat him down on the step and pointed to the car.

     "There she is,Buddy, just like I told you upstairs. His brother gave it to him for Christmas and it didn't cost him a cent. And some day I'm going to give you one just like it…then you can see for yourself all

the nice things in the Christmas windows that I've been trying to tell you about. "

     Paul got out and lifted the boy to the front seat of his car. The shining-eyed older brother climbed in

beside him and the three of them began an unforgettable holiday ride.

1. The street urchin was very surprised when _____.

A. Paul received an expensive car

B. Paul told him about the car

C. he saw the shining car

D. he was walking around the car

2. From the story we can see the urchin _____.

A. wished to give his brother a car

B. wanted Paul's brother to give him a car

C. wished he could have a brother like Paul's

D. wished Paul could be a brother like that

3. The urchin asked Paul to stop his car in front of his house _____.

A. to show his neighbours the big car

B. to show he had a rich friend

C. to let his brother ride in the car

D. to tell his brother about his wish

4. We can infer(推断)from the story that _____.

A. Paul couldn't understand the urchin

B. the urchin had a deep love for his brother

C. the urchin wished to have a rich brother

D. the urchin's wish came true in the end

5.The best name of the story is _____.

A. A Christmas Present

B. A Street Urchin

C. A Brother Like That

D. An Unforgettable Holiday Ride

如图所示，同一平面内有两根互相平行的长直导线甲和乙，通有大小均为I且方向相反的电流，a、b两点与两导线共面，其连线与导线垂直，a、b到两导线中点O的连线长度和甲乙间距离均相等．已知直线电流I 产生的磁场中磁感应强度的分布规律是B=K

I

r

（K为比例系数，r为某点到直导线的距离），现测得O点磁感应强度的大小为B₀，则a点的磁感应强度大小为______B₀，乙导线单位长度受到的安培力的大小为______ N．

患者女性，20岁，未婚。遭受性侵犯后急诊入院， * * 少量出血，患者不配合检查，目前首要的措施是（）

A.心理社会评估

B.全身体格检查

C.询问病史

D.腹部检查

E.盆腔检查

以下哪些不属于活性污泥丝状膨胀的环境因素？（）

A.温度

B.BOD

C.可溶性有机物

D.有机物浓度

在设计滚子从动件盘形凸轮机构时，选择滚子半径的条件是（）。