我国潮汐能最为丰富的海区在（）
A、辽东半岛沿海
B、山东半岛沿海
C、浙闽沿海
D、两广沿海
参考答案：C
We understand _______small changes to our land can have a big impact upon our environment __________ as we know is vulnerable enough.
A．what; which
B．what; where
C．how; where
D．how; which
系列位置效应一般表现是（）的材料记得很好。
A、开头
B、中间
C、后边
D、两头
