13.The reason is____________ smoking tobacco causes illness.A. why B because C. that D. because of
Mary is going on a diet . as she has put on _______recently.
You _______be hungry already—you had lunch only two hours ago.
We _______the letter yesterday, but it didn”t arrive.
Mo Yan was ______the Nobel Prize for his great contributions to literature.
Great changes ______in his hometown in the last twenty years.