In ____ accident _____ knowledge of first aid can make _____ real difference.
| A．the; a; the | B．an; a; a | C．an; the; 不填 | D．a; a; 不填 |
He is only too ready to help others, seldom, _____, refusing them when they turn to him.
| A．if never | B．if ever | C．if not | D．if any |
--The weather is too cold ______ March this year.
--It was still ____ when I came here years ago.
| A．for; colder | B．in; cold | C．in; hot | D．for; hotter |
_____ in thought , he almost ran into the car in front of him .
| A．Losing | B．Having lost | C．Lost | D．To lost |
Take a taxi , ______ you'll miss your train .
| A．and | B．if | C．otherwise | D．or |
--- I ______ so busily recently that I ______ no time to help you with your math.
--- That’s OK. I can manage it by myself.
| A．have been working; have |
| B．have worked; had |
| C．am working; will have |
| D．had been working; had had |