The teacher is writing ____ a piece of chalk on the blackboard while the students are writing ____ink in exercise books.
A. with, in
B. in, with
C. in, in
D. with, with
The worker can make chairs ____ wood, and also can make paper ____ wood.
A. from, of
B. of, from
C. of. of
D. from, from
Mary dropped in ____ Mr Smith, but he wasn' t at home, so she went to drop in ____ Mr Smith's office.
A. on, on
B. at, at
C. on. at
D. at. on
The teacher is not only strict ____ his pupils but also strict ____ his own work.
A. with, with
B. in,in
C. in, with
D. with, in