___ the temperature falling rapidly, we couldn’t go on with the experiment.
23. Allow others the space to voice their opinions, ______ they are different from yours.
20. Could ______ that have a say in the decision do us a favor about the problem?
19. Which do you enjoy ______ you weekend, doing sports or watching TV?
18. She ______ stop whomever she met to tell the story about her Ah Mao.
17. ______, his idea was actually worth practicing.