I tried to work on, but I was so tired that I could no longer _____ .

Have you thatAmy’s a little quiet these days—Yes, I wonder what has happened to her．

Mr. Reed made up his mind to devote allhe had to____ some schools for poor children.[ ]

Sadly, Marie Curie died from ______________ to toomuch radiation.

Do you think you will be able to finish your writing by five o’clock today—________. I’ll be busy with experients all day.