________ if you want to do something, or you won’t be able to do it well.
| A．To try your best | B．Trying you best | C．Try your best | D．Unless you try your best |
Oh, I’m not feeling well in the stomach .I so much fried chicken just now.
| A．shouldn’t eat | B．mustn’t have eaten |
| C．shouldn’t have eaten | D．mustn’t eat |
The naughty boy to me that the hen that there just now had two eggs the day before.
| A．laid; laid; laid | B．lied; lay; laid | C．laid; lay; lain | D．lied; laid; lain |
is even more important is the earth cooled down, water began to appear on its surface.
| A．When; that; when | B．What; whether; as | C．What; that; as | D．lt; whether;  as |
Going on a trip into space must be quite exciting experience.
| A．/;the | B．the; the | C．the; an | D．/; an |
Though having lived abroad for years, many Chinese stillthe traditional customs.
| A．perform | B．pssess | C．observe | D．support |