I have some questions…
1) She must have slept (Is it correct)
2) She must have been sleeping.
3) She must have gone to the mall.
When do we use perfect continuous or perfect simple in conclusion. ?
2) By Friday I could have finish the book, but if I get too busy, I may not.
What does could here express? Possibility? Past or present?
Can we say by Friday I could finish the book……without have to indicate that it is in the present? What is the difference between these 2 sentences?
3) With better communication, the battle could have been avoided and the lives of more than 2 thousand people could have been saved.
What does could mean in this in this case?Is it possibility in the past ?What is the active voice of this sentence?
4) If your friend has helped you a lot and now he is moving to another house so you say I should help him or I must?
I was glad that my computer could be repaired.(correct)
I was glad that my computer could have been repaired.(wrong)
I can't understand the difference between these 2 sentences. Are they in the passive voice? What is the active? Are they in the past? What is the present? I am really confused.