单选题：Will you see to _____that the luggage is brought back? [ ]A..

"When my husband died five years ago, _____ was difficult to go from 'we' to 'me'," said Joe Kita to us.A. I B. thatC. it D. which

I'll wait for you at the gate of the Music Hall. See to ________ that you'll get there on time.[ ]A. yourselfB. itC. allD. everything

I found _________difficult to work out the problem.[ ]A. it's B. thisC. thatD. it

(2014·湖南省部分重点中学3月联考)Many a student________selected to take part in the English competition，and more than one teacher________them on speaking and writing.A．was；has coached　B．were；have coachedC．was；have coached　D．were；has coached

I find _____ important that we practice English every day.[ ]A. it B. this C. that D. what