Объясните: что обозначает окончание "ing"?

Это ну в принципе как окончание -ю плаваю танцую. но не всегда обозначает настоящие время например: i was eating - я ел, прошедшее время чаще всего ing используется у глаголов, а у других достаточно редко, потом в старших классах пройдёшь. рада что )

Когда в основном это действие в данный момент(если глагол)

Idrink tea every morning.i am drinking tea now. i was drinking tea yesterday at 5 p.m. i drank tea ten minutes ago. i have already drunk tea. i had drunk tea by 5 p.m. yesterday. i  will drink tea in 10 minutes.she goes to the zoo every sunday. she is going in the zoo now.she was going in the zoo when we met her.she went to the zoo last monday.she had gone to the zoo yesterday by 6 p.m. she has gone to the zoo twice. she will go to the zoo tomorrow.we visit our friends every week. we are visiting our friends now.we were visiting our friends when their parents arrived.we visited our friends yesterday.we have already visited our friends. we had visited our friends by 4 p.m. last sunday. we will visit our friends next week.

There sre a lot of holidays in winter. the most interesting of them is christmas. people in britain celebrate it on the twenty fifth of december.   some days   before christmas they   decorate christmas tree with toys and colored lights and send greeting cards to their relatives and friends. on christmas eve children put their stocking near the beds and at night santa claus comes and brings presents for them.   on christmas morning everyone sits near the tree and opens his or her presents. they wish "marry christmas! " all people in great britain like this holiday very much.