3 . It’s a good thing that people are going out to enjoy themselves and to discover the great heritage and history, but it is also quite dangerous if they don’t understand ________ fragile the environment is. (用适当的词填空)

4 . She says that both Greece and China have rich cultures and traditions dating back to ancient times, and ________ there is so much to learn from each other. (用适当的词填空)

5 . Libraries have evolved as the public’s needs have changed. In fact, if you haven’t visited your local public library for a while, you may be surprised at ________ it now has to offer. (用适当的词填空)

6 . Ever wonder ________ it would feel like to hide away in a dark cave without being connected to the outside world for 40 days? Fifteen people in France just did that. (用适当的词填空)

7 . When he got older, John started to wonder ________ this process could be used to clean up the messes people were making. (用适当的词填空)

9 . Interestingly, the calligrapher Wang Xizhi from the Eastern Jin Dynasty wrote in his Lanting Xu about _________ literary men composed poetry while drinking from cups left floating and moving along the winding river. (用适当的词填空)