If you swim in a river or lake, be sure to investigate is below the water surface. Often there are rocks or branched hidden in the water.
---You’re writing an essay now , right? ---Yes. I’m busy collecting material ____ to the topic .
The expert offered us another piece of advice , ___ of great help to our program.
---What caused the party to be postponed? ----_____the invitations .
After you’re done with the application form , send it to ___ is in charge of sales.
Hardly _____ closed my eyes ___ I began to make this fantastic dream .