Perhaps you should try some spelling variations:
class teaching » class teachers, classroom teaching
class teacher » class teachers, classroom teacher
china roberto » chang roberto, change roberto, asia roberto
sein time » sein die, sein eine, den time
roberto n » robert _, robert e, robert j
tan ying » ran ying, tan yang, tan yong
fan ying » fan xing, ran ying, jin 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 ying) OR (fan ying)) sein time ((class teaching) OR (class teacher)) china roberto n ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tan ying) or (fan ying)) sein time ((class teaching) OR (class teacher)) china roberto n ;~".
• Adding a wildcard symbol may retrieve word variants: ((tan ying) or (fan ying)) sein time ((class teaching) OR (class teacher)) china roberto n ;*.