1.Babiessleep l6 to l8 hours in every 24 hours, and they sleep less ________ they grow older.
A. while B. as
C. when D. after
2. Ihave been keeping the portrait ________ I can see it every day, as it always reminds me of my childhood in Paris.
A. since B. where
C. as D. if
3. ________ your composition carefully, some spelling mistakes can be avoided.
A. Having checked B. Check
C. If you check D. To check
4. I would never speak to someone like that ________ they said something unpleasant to me.
A. even if B. so that
C. as if D. ever since
5. -Did youremember to return the book to our English teacher?
-Yes. I gave it to him ________ I saw him.
A. once B. while
C. if D. the moment