八．句型转换. (每小题2分, 共10分)

81. It is obvious that he has known the truth.

_____________, he has known the truth..

82. I happened to meet an old friend in the street yesterday.

I met an old friend _____________ ____________ in the street yesterday. 

83. The problem needs discussing.

The problem needs __________ __________ ____________.

84. The government gave an order. All the victims in the earthquake of Yushu County, Qinghai Province were rescued.

The government gave an order _________________________________________________.

85. To master a foreign language is not an easy job.

_______ _______ not an easy job ___________ _________ a foreign language.