Lucy is a very optimistic girl. ______ she is faced with a difficulty, she always sees the bright side.

A．Every time

B．Now that

C．As soon as

D．On condition that

沉降观测宜采用（）方法。

A、三角高程测量

B、水准测量或三角高程测量

C、水准测量

D、等外水准测量