It was 80 years before Christopher Columbus crossed the Atlantic______ Zheng sailed to East Africa
He is the most suitable person _______the task.
_________, the experiment is sure to succeed.
The cost of buying a house in Beijing is higher than ______in Luoyang。
.There are over 58000 rocky objects in _______space,about 900 of which could fall down onto ______earth。
-----Did you enjoy your trip to the town? -----_________. We had driven more than 3 hours before we found the right way.