The student of Class Three have already cleaned their classroom.( 改为否定句)
The student of Class Three ______ cleaned their classroom        .
Her grandfather has been dead since2007 .（对画线部分提问）
________ ______ has her grandfather been dead?
The film began about 20 minutes ago．You are late．(改为同义句)
The film has ________  ________ for about 20 minutes．You are late.
我们应该循环利用塑料袋而不是扔掉它们。(完成译句)
We should reuse plastic bags                  throwing them away.