A study ________ in the USA in 1977 showed that the chemical ASA in aspirin could prevent a stroke.
| A．carrying out | B． carried out | C．working out | D．worked out |
Small sailboats can easily turn over in the water ________.
| A．if not managed carefully | B．if are not managed carefully |
| C．unless not managed carefully | D．unless are not managed carefully |
Tom ______ to me that the rooster which _______ in the corner _______ an egg.
| A．lied; lay; had lain | B．lied; laid; had lain |
| C．lied; lay; had laid | D．lay; lied; had laid |
They did not find ________ to prepare for the worst conditions they might meet.
| A．it worthy | B．it worthwhile | C．it worth | D．worth their while |
You can not imagine that a well-behaved gentleman _______be so rude to a lady.
| A．might | B．need | C．should | D．would |
To their great fear, they found________ in the heaviest snowfall they had never had.
| A．they were catching | B．themselves caught |
| C．they had caught | D．themselves catching |