1They has not learned the formulas, so they will probably fail the test.
2They have not learn the formulas, so they will probably fail the test.
3They have not learned the formulas, so they will probably fail the test.​

Правильный вариант - третий

3They have not learned the formulas, so they will probably fail the test

1)she has got   long black hair , big blue eyes , a  little nose and   nice ears.2)in winter there is a  lot of   snow.3) spring come after the winter .4)winter is the coldest season.5) english celebrate a new year in   winter.1)where was he at  last summer? 2)where will she go for the next  summer? 3) water in the  black sea is clean.4)greens visited   london on last sunday.5)have a  good holiday!

где нужны были артикли там и поставила) 

that dog is very ugly.  my sister is very  beautiful.  не speaks very fast.  he walked slow.  they are very  noisy  in the evenings but are very entertaining to watch.  i wish you'd be quiet.