19. It is reported that China has created the first man-made sun in the world recently, ______ ?
| A．isn’t it | B．is it | C．hasn’t it | D．has it |
You didn’t believe John won the first prize at the speech competition, ______?
| A．did he | B．didn’t he | C．did you | D．didn’t you |
I had reached a point in my career _____ I needed to decide which way to go．
| A．why | B．which | C．when | D．where |
Here are some new computer programs _____ for home buildings．
| A．designing | B．design | C．to design | D．designed |
sweet and fresh, this kind of food is so popular with local people and the tourists．
| A．Smell | B．Smelling | C．To smell | D．Smelt |
Always read the label ______ you wash your clothes．
| A．before | B．unless | C．since | D．until |