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