翻译成英文：“我经常在周末去爬山”

He often climes a moutain on the weekend.
相信我，没错的

He often climbs the hill at the weekend.
绝对没错的，我就是刚学的，这是一般现在时，爬山应该是climb the hill，第三人称一般现在时要加s. at the weekend和on weekdays是固定搭配。

I often climbing mountain on weekend.

He often climbs mountains at the weekend.

He often goes to climb the mountain on weekends

He often goes climbing on weekends