Put the verbs in brackets in the correct form, present simple or present continuous. 

Diana ______ (sometimes forget) to do all her homework.
I _______ (try) to do this exercise at the moment.
The students ______ (just start) to get to know  each other.
Our teacher ______ (always tell) us a joke at the beginning of the lesson.
Our English tests _____ (get) harder and harder!
Learning new vocabulary ____ (often take) a lot of hard work.