Perhaps you should try some spelling variations:
teaching chang » teaching change, teaching china, teaching chunks
chang roberto » chase robert
time class » five class, site class, time last
time case » time based, time bases, time cost
roberto e » robert e, roberto n, roberto f
tan yang » dan yang, tan ying, tan yong
fan ying » fan xing, ran ying, tan ying

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tan yang) OR (fan ying)) di ((time class) OR (time case)) teaching chang roberto e ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tan yang) or (fan ying)) di ((time class) OR (time case)) teaching chang roberto e ;~".
• Adding a wildcard symbol may retrieve word variants: ((tan yang) or (fan ying)) di ((time class) OR (time case)) teaching chang roberto e ;*.