About how many elements _____ make up most of the substances we meet in everyday life
| A．it is which | B．what it is | C．is it that | D．it is that |
____ they did not believe him, what would they do then?
| A．Suppose | B．Supposed | C．I suppose | D．You suppose |
John shut everybody out of the kitchen ____ he could prepare his grand surprise for the party.
| A．which | B．when | C．so that | D．for |
一Tell us, Mark ,what is the ____ of the American Civil War?
一 Well, is it because the black slaves wanted freedom?
| A．effect | B．cause | C．result | D．reason |
So much of interest ______that most visitors simply run out of time before seeing it all.
| A．offers Beijing | B．Beijing offers | C．does Beijing offer | D．Beijing does offer |
My sister, an inexperienced rider, was found sitting on the bicycle ______to balance it.
| A．having tried | B．trying | C．to try | D．tried |