33. I cannot understand__________the boy alone.
| A．why she left | B．why did she leave | C．why she had left | D．why had she left |
--- He was nearly drowned once.
--- When was _____?
--- _____was in 1998 when he was in middle school.
| A．that; It | B．this; This | C．this; It | D．that; This |
—It’s nice.Never before____ such a special drink!
—I’m glad you like it.
| A．I have had | B．I had | C．have I had | D．had I |
We feel our duty to make our country a better place.
| A．it | B．this | C．that | D．one |
_____is our belief that improvements in health care will lead to a stronger, more prosperous economy.
| A．As | B．That | C．This | D．It |
—There is still a copy of the book in the library.Will you go and borrow_____?
—No，I’d rather buy_____in the bookstore.
| A．it；one | B．one；one | C．one；it | D．it；it |