86.  写出同义句(It.......since.....)He has been in the club for two years.=He joine

86.  写出同义句(It.......since.....)He has been in the club for two years.=He joined the club two years ago.

87.  变为被动语态 People have acquired knowledge through exploration.

88.  我们保护自然的原因是我们能从中受益。（The reason why ....is .....     benefit from）

89.  变为强调句型。He did not go to sleep until midnight.

90. “only+状语”位于句首的倒装句

____________(只有)you ask many different questions ___________________ (你才会获得)all the information you need to know.

86. It is/has been two years since he joined the club.

87. Knowledge has been acquired through exploration.

88. The reason why we protect nature is that we can benefit from it.

89. It was not until midnight that he went to sleep.

90. Only if ,  can/will you acquire