Когда пишется learn, а когда study?

It's a hospital. You (can’t/mustn’t)…… smoke.I (can/may)…….speak Arabic fluently when I was a child and we lived in Morocco.(Must/Can)…….you stand on your head for more than a minute? No, I (can’t/may not)… People (can’t/mustn’t)……. walk on grass.Drivers (may/must)……. stop when the traffic lights are red.(Can/May)……I ask a question? Yes, of course.(Can/May)…….you speak Italian? No, I (can’t/may not)…… .I am afraid I (can’t/mustn’t) ….. help you now.Don't stand up! – You (can’t/may not) stand up!I'd like to see your children. – (May/Must) I see your children?

проспрягайте данные глаголы в Past Continuous: to do, to make, to play, to watch, to listen, to read, to write, to learn, to study, to speak, to translate, to check, to correct, to cry, to go, to come, to receive