After a 3-week winter vacation， students usually some weight when they return to school.

Look! Tom is getting the first place. _________ fast runner he is!

Two-thirds of the land ________ covered with green grass and the rest _______ covered with pine trees.

I’m not quite sure how to get there, ———- I’d better _____ a map.

Further space exploration has been _______ with the rapid development of China’s science and technology