安装管道法兰和阀门的螺丝时，为了校正螺丝孔，用（）伸入螺丝孔内触摸，以防伤害。
A.手指
B.撬棒
C.二者均可
D.手电筒
参考答案：B
在“探究凸透镜成像规律”的实验中，把蜡烛放到离凸透镜15cm处，光屏上出现倒立、等大的实像，若将蜡烛向凸透镜靠近6cm，适当移动光屏后在光屏上可以看到______的像．
---How well do you know the Opera House?
--- I know the place very well. I Sydney many times.
A．have been in
B．have been to
C．have gone to
D．have arrived in
