国内大多数中小氮肥厂都采用固定床间歇气化技术，是由于这种技术工艺先进，而且较为成熟，投资较低。
参考答案：错
_______the sun was not yet up, many people were already taking exercise in the square
A．As
B．If
C．Though
D．Because
（）促使植物生根。
A.增加水分
B.提高温度
C.增加氮肥
D.增强光照
