. While typing, Helen has a habit of stopping _____ to give her long and flowing hair a smooth.
31. The decision ______ Internet addiction(成瘾)as a mental disorder has caused much debate.
30. As we watched the panda, we stood still, ______ to one another.
29. Contrast may make something appear more beautiful than it is when ______ alone.
28. At a rough look, the area of the city is about ______ the old one.
27. The Grand Theatre in Shanghai is open to visitors during the daytime ______ there is a performance going on.