Before you__the street,you must look to the left and then right.在你过马路前,必须左右看一看.Before you__(go across)the street,you must look to the left and then right.应该填go across 还是 going across.（P.S.我知道可以填cross）

Before you__the street,you must look to the left and then right.
在你过马路前,必须左右看一看.
Before you__(go across)the street,you must look to the left and then right.
应该填go across 还是 going across.（P.S.我知道可以填cross）