Choose the correct option to complete each sentence.

1. I can't make any sense (with / of / in) this text. There are a lot of difficult words.
2. I don't think students should have access (for / in / to)
the Internet during tests.
3. For me, it's difficult to concentrate (to / on / at) one
subject for a long time.
4. Our teacher told us to learn the irregular verbs in English (by / for / with) heart.