вместо точек: The grass is wet. It ... A)has been raining Б)rained B)was raining c)has rained

The grass is wet. It has rained.

The first sentence is in Present Indefinite (is). We use Present Perfect in the second sentence. Present Perfect I used for past action which result connects with present.

Present Perfect is formed with the help of the auxiliary verb to have. We use has for the third person singular (he, she, it). We use the third form of verbs (rained).

Negative — have / has + not + the third form of verb.

 It has not rained.

Interrogative — have / has + subject + the third form of verb.

 Has it rained?