It is said that many streets in this city have been ______ for cultural protection.

 Worried about the time ________， Mary had made a list of the sites she wanted to see in Beijing.

Even students with        intelligence can be excellent students after improving their study habits.

--- My watch is nowhere to be found. --- Don’t worry! I’m sure it will ____ sometime when you’re not looking for it. 

 It is high time that we started to consider what ________  we should take to reduce heavy smog caused by traffic fumes and other pollutions.