单项选择题
A．gradually B．suddenly C．greatly D．frequently
Greene spent a brief time at Cambridge.（）A．hardB．shortC...
单项选择题Greene spent a brief time at Cambridge.（）
A．hard B．short C．good D．long
A number of theories have been proposed to explain the ...
单项选择题A number of theories have been proposed to explain the situation（）
A．tested B．suggested C．used D．announced
We explored the possibility of expansion at the confere...
单项选择题We explored the possibility of expansion at the conference（）
A．investigated B．offered C．included D．accepted
