As is known to us, theory is based on practice and servers practice. A. by chance B. in turn C. in return C. by turn
With the help of high technology, many new substances(物质)______in the past years.
---- Will Joe attend the party? ----- If his wife won’t go to the party,_________.
----- Can I go back home now? ----- You______ to leave until you ______ your work.
----- Are you used to______ in the north with the old couples? ----- Yes, I am glad to find out that coal is used______ electricity for home use.
All the neighbors think highly of this family, _________ the parents are treating their child like a friend.