--- I ______ so busily recently that I ______ no time to help you with your math. --- That’s OK. I can manage it by myself.
______ metals are good conductors, silver ______ the best conductor of all.
Instead, he seemed to see Tom ’s face, with the wide smile he ______ whenever he told a joke.
----- I can ’t see the words on the blackboard clearly. ----- Why, your eyes need _____ perhaps you need _______ glasses.
The typewriter _______ there all week.
This is the plane _______ he went to Shanghai ______ business.