环境现状调查的方法主要有收集资料法、（）和遥感的方法。
A．现场调查法
B．排除法
C．抽样调查法
D．等级分析法
参考答案：A
It’s time for class，please _______ quiet.[ ]
A. is
B. be
C. are
D. /
My aunt _____ here by now, for she took the early bus.
A．must arrive
B．can arrive
C．may arrive
D．ought to have arrived
My aunt _____ here by now, for she took the early bus.