Tarzan C1 Grammar Adventure

Which sentence uses a correct relative clause with a preposition?

• Tarzan’s treehouse, that he sleeps in, stands near the river.
• Tarzan’s treehouse, in which he sleeps, stands near the river.
• Tarzan’s treehouse in which sleeps, stands near the river.
• Tarzan’s treehouse, in that he sleeps, stands near the river.

Explanation

In a non-defining relative clause with a preposition, place the preposition before which: in which he sleeps.