We can never expect_______bluer sky unless we create_______less polluted world.
| A．a; a | B．a; the | C．the; a | D．the; the |
Every morning I get up at 6:00 because I have two dogs ______ at the door for me to take them out for the routine walk.
| A．to wait | B．wait | C．waited | D．waiting |
Guess what! I came across my primary school science teacher this morning, ______ I have lost touch for almost 20 years.
| A．of which | B．when | C．with whom | D．who |
After Tom had finished some paper work, he ______ interviewing the applicants.
| A．starts | B．had started | C．started | D．has started |
It takes ______ to talk to others on the team when that might expose some of your own weaknesses or ignorance.
| A．energy | B．patience | C．wisdom | D．courage |
______her ambition of becoming a professional singer, she has been training very hard since an early age.
| A．Realizing | B．To realize | C．Having realized | D．To have realized |