The Japanese Verb - To do

The Japanese verb "To do - Suru" is the most important verb to learn.

The plain form is - Suru する
The polite form is Shimasu します

Saying Suru or Shimasu alone is like saying speaking in a future tense, it means "I will do it".

Many Japanese nouns take the  + Sure form which makes it easy for learners of Japanese.

For example Diet wo shimasu ダイエットをします。Means I am going to go on / start a diet.

The plain tenses are as follows.

Shita した - to have done / did
Shitai したい - to want to
Shitakunai したくない - to not want to do
Shiteiru している - to be doing

The polite tenses are

Shimashita しました - to have done / did
Shiteimasu しています - to be doing.

Shitai an Shitakunai + desu will make the polite form.