据统计，明代的皇帝年号出现较多的是（）、万历、嘉靖和崇祯。
参考答案：永乐
It was ___ it was raining so hard that we had to stay at home all day.
A．since
B．for
C．as
D．because
矿用汽车在行驶时，举升手柄应始终保持在（）位。
