The fact has worried many scientists ______ the earth is becoming warmer and warmer these years.
| A．what | B．which | C．that | D．though |
- Will you be available at three o'clock tomorrow afternoon?
- No. I ______ a lecture then.
| A．are attending | B．will have attended | C．will attend | D．will be attending |
My own handwriting style is different from _______of my friends.
| A．it | B．this | C．that | D．one |
Would you like some more coffee?
| A．Thank you! It's kind of you | B．Great! Well done | C．Well, it doesn't matter | D．OK. It's up to you |
________energy, we turn off the lights for Earth Hour on the last Saturday in March
| A．Saving | B．To save | C．Saved | D．Having saved |
American students take part in a wide variety of after-school activities _______ they develop their social skills.
| A．where | B．which | C．that | D．what |