质量为m的物体,在距地面h高处以g3的加速度由静止沿竖直方向加速下落到地面,下列

题型:多选题

问题:

质量为m的物体,在距地面h高处以

g
3
的加速度由静止沿竖直方向加速下落到地面,下列说法中正确的是(  )

A.物体的重力势能减少

mgh
3

B.物体的机械能减少

mgh
3

C.物体的动能增加

mgh
3

D.重力做功mgh

考点:动能定理
题型:多选题

阅读理解。

     Sick men and women were sitting on their chairs in the doctor's waiting room. They all looked sad

except Tom. He was playing with some cards. Just then the doctor came to say he was ready for the

next one. Tom jumped up and entered the doctor's room in a hurry.

     Before Tom could say a word, the doctor made him lie down on the bed."Now let me listen to your

heart." Tom tired to speak, but the doctor told him not to say anything. "I'll take your temperature." Tom

tried to sit up, but the doctor stopped him. After a while, the doctor said, "Well, you don't have a fever

(发烧), boy. In fact, there's nothing wrong with you.""I'm quite well, doctor." Tom said."I just came here

to get some medicine for my grandma."

1. In the doctor's waiting room Tom _______.

A. looked sad

B. was playing with some cards

C. was talking with others

D. was very happy

2. Before the doctor listened to Tom's heart, he _______.

A. asked Tom how old he was

B. asked Tom to sit down

C. made Tom lie down on the bed

D. talked with Tom for a few minutes.

3. The doctor thought _______.

A. Tom had a fever

B. there's something wrong with Tom

C. there's something wrong with Tom's heart

D. nothing is wrong with Tom

4. Tom came to the doctor's room because he _______.

A. was ill

B. wanted to see the doctor

C. wanted to get some medicine for his grandma

D. had a fever

5. Which is right?

A. Tom played with some cards in the doctor's room.

B. The doctor told Tom to enter his room quickly.

C. The doctor looked over Tom's grandma.

D. Tom's grandma needed some medicine.

题型:多选题

为颈内动脉的延续,走行于大脑外侧沟的动脉为()
由左、右椎动脉合成的动脉为()
连接颈内动脉和大脑后动脉的为()

A.基底动脉

B.前交通动脉

C.后交通动脉

D.大脑前动脉

E.大脑中动脉

题型:多选题

常见前纵隔肿瘤是()

A.胸腺瘤

B.神经源性肿瘤

C.肉瘤

D.平滑肌瘤

E.支气管囊肿

题型:多选题

时效用于各种精密工件消除切削加工应力,保持尺寸稳定性.

题型:多选题

2011年7月19日,社会各界在拉萨举行了隆重的庆祝大会,庆祝西藏和平解放

A.40周年

B.50周年

C.60周年

D.70周年

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