Great changes _______ in his hometown in the last twenty years.
| A．were taken place | B．have taken place |
| C．have been taken place | D．took place |
.
Medical ______ shows that men are more likely to have heart attacks than women.
| A．expectation | B．evidence | C．experience | D．exchange |
.
Several years had passed ______ I finally realized the true value of friendship.
| A．when | B．that | C．after | D．before |
.
All passengers ______, please fasten your seat belts and remain seated ______ the plane is landing.
| A．on board; before | B．abroad; since | C．on the board; after | D．aboard; when |
.
Unfortunately, it was in Yushu County, ______ a 7.1-magnitude earthquake happened on April 14, 2010, ______ a large number of students were buried inside damaged schools.
| A．which; when | B．that; that | C．where; that | D．where; which |
.
______ World Exposition in 2010 is the first registered World Exposition in ______ developing country.
| A．/; a | B．The; a | C．The; / | D．/; the |