You have left the light on Oh. soihave__and tum it off

who's that woman standing by our English teacher? It _be Jims mother, I'm not sure

A.can

B.should

C might

D.must

bike-sharing is convenient and idon ' t need to buy a bike for_

A.I

B.my

C. mine

D.myself

Why do many people buy things online on the 1lth of November every year? They think the things on sale are_

A. much cheaper

B. much lower

C. more expensive

D .much higher

_in his study,hedidn'tknow that all the others ha

A Burying

B Buried

C.Buried himself

D. He buried

Have you seen Mr Green? Yes, I saw him at the school gate. He_ with the headmaster.

A is talking

B.was talking

C. talked

D.has talked

-john is very If he promise to do something he'll do it.

A.independent

B.reliable

C.confident

D.flexible

My desk-mate has difficulty_ spelling some of the words in American English while, I have trouble_ intonation

A. with: with

B. in; with

C. in; in

D. with; in

?

A. He arrived there half an hour late

B. Tom is the most honest boy in his class

C. I really hope to

D. It is a great honor for me to be here

下列说法正确的是( )。

A. α射线与γ射线都是电磁波

B. β射线为原子的核心外电子电离后形成的电子流

C. 用加温、加压或改变其化学状态的方法都不能改变原子核衰变的半衰期

D. 原子核经过衰变生成新核，则新核的总质量等于原核的质量

带电粒子进入云室会使云室中的气体电离，从而显示其运动轨迹。图5是在有匀强磁场的云室中观察到的粒子的轨迹，a和b是轨迹上的两点，匀强磁场B垂直纸面向里。该粒子在运动时，其质量和电量不变，而动能逐渐减少。下列说法正确的是( )

A. 粒子先经过a点，再经过b点

B. 粒子先经过b点，再经过a点

C. 粒子不带电

D. 粒子带正电