He needs to go _____ a forest on his way home every day.

For theme parks, ______ is the key to _____ visitors, which contributes to the success of running them. [ ]

Some plants are so difficult to grow that they can only ______ in a perfectly clean environment.

The team trekked _____ the jungle to look for the living tigers.

Must I take the medicine every day—No, you _______.