— What are the _______ doing there?
— They are busy _______ their science experiment.
A.Boys students; to do | B.Boy students; to do |
C.Boys students; doing | D.Boy students; doing |
— What are the _______ doing there?
— They are busy _______ their science experiment.
A.Boys students; to do | B.Boy students; to do |
C.Boys students; doing | D.Boy students; doing |