任何能跨越天然屏障、在浅海之间快速大量运输含有浮游生物水体的机制都有可能促进海洋生物的入侵。
参考答案：对
— I usually go there by train.
— Why not _______ by boat for a change? [ ]
A. to try going
B. trying to go
C. to try and go
D. try going
检查牙隐裂的方法是（）.
A.视诊探诊
B.叩诊咬诊
C.碘酊染色
D.温度测验
E.X线检查
