Believe it or not，I'm sure that is ________ people call the six sense.
| A．when | B．what | C．which | D．why |
___ from space, the earth with water ___70％ of its surface looks like a "blue blanket".
| A．Seen; covered | B．Being seen; covers | C．Seeing; covering | D．Seen; covering |
____ more attention, the trees could have grown better.
| A．Given | B．To give | C．Giving | D．Having given |
Someone is ringing the doorbell. Go and see ______ .
| A．who is he | B．who he is | C．who it is | D．who is it |
_________ I will visit Brazil during the 2016 Olympic Games.
| A．If I am possible | B．If it possible | C．If I possible | D．If possible |
___________, I have never seen anyone who’s as wise as John.
| A．As long as I have traveled | B．Now that I have traveled so much |
| C．.As I have traveled so much | D．Much as I have traveled |