中考英语重要短语的用法及区别：across , cross, crossing, through, ast
（1）cross 意为横过， 穿过为动词，相当于walk（go，run）across
Look both ways before you cross the road.
（2）across意为横过，穿过为介词，不作动词，不能作谓语，常放在动词之后，如：go across
He walked across the field.
（3）through 是介词，含有从中间穿越之意，表示四周含有物体的穿越。
The ball went through the window.
（4）past既可作形容词也可作副词，做副词时有：穿过，越过之意。
Will you be going past my house on your way home？
（5）crossing意为渡口，人行横道，（铁路与公路的）交叉点。
All the cars should stop before the zebra crossing.