Leonardo da Vinci (1452-1519) ____ birds kept in cages in order to have the pleasure of setting them free.
A. is said to be buying B. is said to have bought
C. had said to buy D. has sad to have bought
They paid fifty percent of _____ they were able to earn to the state．
A．that B．which C．what D．whom
My sister is _______ about what she eats, otherwise she would not be so thin.
A. special B. curious C. particular D. specific
I know a little bit about the city as I __________ there for one year in my youth.
A. am studying B. had studied C. studied D. have studied
While working in the countryside, the students a great deal of knowledge on plant life.
A. looked up B. picked up C. put up D. called up
Criticism and self-criticism _____ necessary _____ it helps us to correct mistakes.
A. is, in that B. are, in that C. is, in which D. are, at that
