The ratio of the work ______ by the machine to the work _____ on it is called the efficiency of the machine.
A: to do ...to do
B: doing....doing
C: having done ... having done
D: done ...done
A: to do ...to do
B: doing....doing
C: having done ... having done
D: done ...done
举一反三
- The ratio of the work done by the machine _________ the work done on it is called the efficiency of the machine.
- The ratio of the work done by the machine ______ the work done on it is called efficiency of the machine. A: against B: to C: with D: for
- With a lot of work ______, he had no time to talk with us. A: to be done B: to do C: doing D: done
- The thief caught on the spot by the policeman denied______ anything. A: to do B: to have done C: doing D: having done
- I only got round to ____ this a few days ago. A: do B: doing C: having done D: have done