翻译英语:当这个小男孩在街上走的时候,外星人来了.

When the little boy in the street, aliens was coming.
或While the little boy was in the street, aliens was coming.

When the little boy walking in the street when the aliens come.

When the little boy is walking in the street,the ET comes.

Some alians arrived when this boy is walking in the streets.

When the boy was walking on the street,the alient came.

When the little boy in the street, alien is coming.

ET. comes when the boy is walking on the street.