Sorry, I______my homework at home.
—It’s difficult to get to the other side of the river.—I think a bridge ________ over the river.
She said she returned the book to the library.I'm sure she ________.
一Do you know why he didn’t ________ a word when he ________ to?—Because he was too nervous.
—Do you know the price of the ticket?—Yes.Each ________ ¥180.
You mustn’t go off on your own,because you ________ get lost in the mountains.