The rivers will become dirtier and dirtier________ we take action to protect them.
| A．since | B．if | C．until | D．unless |
---Would you like some more rice? ---______. I’m full.
| A．No, thanks | B．Yes, thank you | C．I’d love to | D．Yes, please |
I won’t buy it because it’s too ______.
| A．expensive | B．more expensive | C．most expensive | D．much expensive |
There’s some litter on the floor. Please ______.
| A．pick up it | B．pick it up | C．pick them up | D．pick up them |
---What’s your favorite ______? ---Hamburger.
| A．food | B．drink | C．fruit | D．clothing |
My friend Max started to play football ______ he was seven years old.
| A．since | B．when | C．if | D．while |