______ was most shocking about the tornadoes in America was that they threatened six states and killed more than 100 persons.
A. That B. Which C. Why D. What
The disappearance of dinosaurs made _______ the evolution and dominance of mammals on the earth.
A. it was possible B. it possible C. possible to be D. possible
I felt most angry about the way ______ I was treated when I was shopping.
A. when B. that C. which D. where
Regarding China-US differences on human rights issues, Hong said the two sides can enhance mutual understanding through dialogue ______ on equality and mutual respect.
A. based B. to base C. basing D. base
When we start gazing into the night sky with a telescope, soon we’ll be astonished by the realization _______ we and our world are part of this giant system.
A. which B. whether C. that D. as
Karaoke, which was invented by the Japanese, ______ both wonders and problems.
A. has been produced B. was produced C. produced D. has produced
