21．I’m vey busy toady______,I have much work to do today

Like some of my classmates,I cannot live up to my teachers’expectations; ________I let them down.[ ]

.—I’m sorry, but there’s no smoking room in this section on the train —Oh, I _____ that, and I won’t smoke again

s visit, before I left the US．，I visited the Yu Ying School, a public school near the White House in Washington, D.C.” said Mrs. Obama.

Would you like _____ cakes They are so delicious. -____. I’m full.