The charity organization has launched a TV appeal _______ people should do as much as they could to help those survivors in the earthquake.
A. what B. when C. that D. where
It has been widely accepted that only when the students take an active part in the class activities _______ the most effective.
A. teaching will be B. will teaching be
C. has teaching been D. teaching has been
. With the whole village _______, the villagers had to move to higher land, waiting for help.
A. flooding B. having flooded
C. flooded D. to be flooded
The UN does not have its own army. _______, it borrows soldiers from different countries.
A. Moreover B. Anyhow C. Instead D. Somehow
. A nature reserve for white-flag dolphins was set up in 1992, _______ boats have been
prohibited from sailing around since then.
A. where B. which C. when D. what
It is surprising that Jack, who is only 39 years old, _______ in the field of engineering for 20 years when he entered the company last month.
A. worked B. had worked C. has worked D. working
