新安装或大修后的变压器投入运行，重瓦斯保护必须投入（）位置。
参考答案：跳闸
从一副扑克牌(54张)中抽一张牌，抽到牌“K”的概率是 。
The teacher told us that the sun _____bigger than the earth. [ ]
A. is
B. was
C. has been
D. will be
