Nuclear radiation is said __________ the biggest health challenge in Japanese Earthquake over the past few months．
| A．being | B．to be | C．to have been | D．that it is |
We have no idea at all __________.
| A．where he has gone | B．where did he go |
| C．which place has he gone | D．where has he gone |
_______is certain ______ the Normans conquered England in 1066 and then English changed.
| A．That; that | B．It; what | C．That; what | D．It; that |
Many years of hard work_______ his great success in the development of this new type of material.
| A．due to | B．thanks to | C．contributed to | D．looked into |
Danby left word _______he would call again in the afternoon .
| A．who | B．that | C．as | D．which |
I was surprised by his words ,which made me recognized ______silly mistakes I had made .
| A．what | B．that | C．how | D．which |