Choose the correct tense in the sentences.
1.I usually play/am usually playing tennis on Saturdays.
2.I'm sorry I can't lend you my pen. I use/am using it myself at the moment.
3.The leaves are falling/ fall from the trees in the autumn.
4.Exams are getting/ get more and more difficult.
5.The eart goes/is going around the sun. .
6.Sue is using/uses a friend's bicycle until her car is repaired.
7.I am doing/do my homework, so don't disturb me.