When I was a child, I ___ climb trees easily.
Could
You ___ use your phone in the library. It’s forbidden
Can’t
Students ___ bring their ID cards to the exam.
Have to
She ___ run very fast when she was younger.
Could
You ___ drink more water, it’s good for your health.
Should
Workers ___ wear helmets at all times on this site.
Have to
Yesterday, Mark didn’t come to class. He ___ (1) been sick, or he ___ (2) overslept. Both are possible explanations.
Might/may
The lights are off and nobody is answering the phone. They ___ (1) gone out, or they ___ (2) be sleeping.
Could have/might
She failed the exam. She ___ (1) studied harder, and she ___ (2) wasted so much time watching TV.
should have / shouldn’t have
The meeting was important. We ___ (1) arrived on time, but the traffic was terrible. At least we ___ (2) called to explain.
should have / could have
Peter looks very happy. He ___ (1) received good news, or he ___ (2) passed his driving test.
must have / might have
The museum was closed yesterday. We ___ (1) entered without permission, and we ___ (2) waited until it opened instead.
could / should have
