Choose the best answer

I sometimes waver ________continuing to study and starting up.

We benefit greatly ____________the medicines and other products that biodiversity provides.

Choose the best answer

The campaign had a considerable impact ______ the environment. 

You should concentrate _________what the interviewer is saying and make a real effort to answer all the questions the interviewer asks.

They prevented me______ entering the house.

We are here to provide you_____ the best service possible.

He succeeded________ getting a scholarship.