_________ caused the accident is still a mystery.
| A．How | B．What | C．That | D．Where |
The famous star got injured before her concert,made her fans worried.
| A．who | B．which | C．that | D．what |
It has been proved thathard leads to success.
| A．work | B．works | C．worked | D．working |
The palace you visited yesterdayabout five hundred years ago.
| A．builds | B．built | C．is built | D．was built |
—Shall we go shopping?
—Sorry, webuy anything now because none of the shops are open.
| A．mustn’t | B．needn’t | C．can’t | D．shouldn’t |
The boy mademistakes in this exam so he got a higher grade.
| A．some | B．fewer | C．many | D．more |