Complete the sentences with can/can't, could/couldn't or the correct form of be able to

Giúp mình bài này với ạ!!
Complete the sentences with can/can't, could/couldn't or the correct form of be able to. Some sentences may have more than one correct answer.
1. She...... understand two languages when she was a child.
2. I woke up late, but I ....... get to the lesson on time.
3. I......work late at night, but it's difficult for me to work in the morning.
4. I worked hard, but I...... finish the report yesterday
5. I hope Sara......come today - she has been ill recently.