The ______ is that the new machine will arrive tomorrow.
| A．chance | B．luck | C．happening | D．accident |
I ________ pay Tracy a visit, but I am not sure whether I will have time this Sunday.
| A．should | B．might |
| C．would | D．could |
The book was written in 1946, __________ the education system has witnessed great charges.
| A．when | B．during which | C．since then | D．since when |
—Where did you get to know her?—It was on the farm __________ we worked.
| A．that | B．there | C．which | D．where |
Some pre-school children go to a day-care center, __________ they learn simple games and songs.
| A．then | B．there | C．while | D．where |
After graduation she reached a point in her career __________ she had to decide what to do.
| A．that | B．what | C．which | D．where |