Complete the sentences with can/can't, must/mustn't or may.
1-You forget to offer your mother a present on Mother's day.
2-You brush your teeth regularly.
3-Birds fly but elephants
4-It rain this afternoon. There are many grey clouds in the sky.
5- you lend me some money, please?
6-I speak French but I can't write it .
7-You eat or sleep in class.
8-Students switch off their mobile phones in class.
9- Surfing the net become an addiction.
10- The lesson is over pupils. You leave now.Good bye.
11- You borrow three books a week from our library.
12-Medicines cure us when we are ill but they be harmful if we take them without our doctor's prescription.
13-Teachers and students go to school late.
14-I ski at any time of the day here but I bring my equipment first.
15-We help the elderly as much as we can.