Silk from China found its way to India, the Middle East and Rome, spices(香料) and glass, which was not known to China.
With more forests being destroyed, huge quantities of good earth_______ each year.
_______in the forests for nearly a week, the two students were finally saved by the local police.
The place______ the bridge is supported to be built should be _____ the cross river traffic is the heaviest
_____ walk is expected to last all day, so bring_____ packed lunch.
----Could you do me a favor and take these books to my office? ---- Yes._______.