日本語のおしゃべり

Japanese Language
「Sentence Structure」

The te form of a verb, followed by wa ikenai or  wa ikemasen, is used to tell someone that they should not, or is not allowed to do something.
NOTE: The verb komaru ("be troubled") or the na-adjective dame da ("no good," "useless") may be used in place of ikenai (examples 2, 3).

Examples:
水が汚いから川で泳いではいけません。
Mizu ga kitanai kara kawa de oyoide wa ikemasen．
The water is dirty, so you must not swim in the river.

テレビをつけたまま寝てはだめですよ。
Terebi o tsuketa mama nete wa dame desu yo.
You must not go to bed leaving the TV on.

まだこの書類を捨てては困ります。
Mada kono shorui o sutete wa komarimasu.
You must not throw away these papers yet.

Hope this helps!

じゃまたね！

°˖ ✧◝(○ ヮ ○)◜✧˖ °こゆうきあいはら°˖ ✧◝(○ ヮ ○)◜✧˖ °