—I think recycling books and paper is useful．
—________
A．I quite agree．
B．I have no idea．
C．We shouldn’t use such things．
D．That’s a great idea．
—Where is David?
—I think he________Australia．
A．has gone to
B．has been
C．has gone
D．has been to
—Have you packed the camera yet?
—Yes，of course．I________it last night．
A．have packed
B．was packed
C．packed
D．had packed
Homo erectus pekinensis(北京人)________in Zhoukoudian Village，on the Longgu Mountain，Fangshan District，Beijing．
A．has discovered
B．was discovered
C．is discovered
D．will discover
Grandma________us stories when we were very young．
A．used to tell
B．was used to tell
C．is used to tell
D．was used to telling
—________free education，the poor children in my hometown can go back to school．
—So can the children in my hometown．
A．Thanks to
B．Instead of
C．As for
D．Towards
