The て-form is also used in the pattern て-form + もいい, which is commonly used to ask for permission or
whether something is acceptable. The word いい, as you learned previously, means good or OK.
So you can think of the literal translation of this grammar point as, Is it alright to …?
Conversely, you can use the pattern て-form + はいけません to say that something is not permitted.
Check out the sentences below for some examples for how this pattern may be used in context.
Can I smoke here? (Is smoking allowed here?)
ここでタバコを吸ってもいいですか？ koko de tabako wo sutte mo ii desu ka?
Can she come too?
彼女も来てもいいですか？ kanozyo mo kite mo ii desu ka?
In Japan, wearing shoes inside the house is not allowed.
日本で、家の中で靴を履いてはいけません。 nihon de, ie no naka de kutu wo haite ha ikemasen.