Sorry, it’s being a while since the last lesson as I was busy helping my wife taking care of my twin babies.

Today, I will cover “~ku narimasu” which means “become something”.

Example
Enpitsu ga nagai desu + Mijikaku shimasu = Mijikaku narimashita
Long pencil + Shorten it = Became Shorter

For adjective ends with “i”, “ku narimasu” should be used otherwise “ni narimasu” shall be used. For example :

Byōki >> Genki = Genki ni narimashita
Sick >> Fine / Well = Became well

Fuyu >> Haru = Haru ni narimashita
Winter >> Spring = Became (Changed) to Spring

Other Usage
I have already became 20 years old – Mō 20 sai ni narimashita
Still haven’t reach 20 years old – Mada 20 sai ni wa narimasen

As usual, for negative answer “ni wa” should be used instead of “ni”. For the ~ku narimasu, ~ku arimasen shall be used.