Complete the sentences with the correct passive form of the verbs. 1) In my opinion more research into the new pills ought to / to do before people started buying them. 2) Their sleep can / to disturb by any noise. 3) I really doubt that wild animals can / to hold in the zoos safely. 4) It is evident that the results of the exams must / to check before they were revealed.
1. In my opinion more research into the new pills ought to be done before people started buying them.
2. Their sleep can be disturbed by any noise.
3. I really doubt that wild animals can be held in the zoos safely.
4. It is evident that the results of the exam must he checked before they were revealed.