六．单词拼写（5分）
81. University professors often ___________ (抱怨) that students are handing in papers using false information they found on the Internet.
82.Having made good preparations, the students all made very wonderful ____________(陈述).
83．They considered themselves to be s_________to black people.
84. Lightning usually a__________ thunder.
85. The teacher did not explain its grammatical f_________.
86.Who can still have _________ (信任) in you despite your shortcomings?
87.They realized there was some __________ (潜在的) danger behind the case.
88.He tried to apply for the patent. But his a___________ was not accepted at all.
89. Her books enjoy a high p_________ among teenagers in many countries.
90.Their country is passing through__________(麻烦的) times.