Question

Complete the following

I was very ill last summer, and for two weeks..........

Answer 1

have been sick since the last week is ungrammatical.

The choice between the other two depends on the context. I have been sick since last week emphasises that you started being sick one week ago and that you are still sick. I have been sick for the last week indicates that your sickness is of at least seven days duration, but it is vaguer about when your sickness started. It could have started a week ago, but it doesn’t exclude the possibility that you were feeling unwell before

Answer 2

I was very ill last summer,and for two weeks I am feeling better.

Hope it helps you...✌️‼️