怎样选择判断用that而不能用when（强调句和定语从句）ItwasonthemorningofMay1stwhenImetmyfriendattheairport.（when为什么错?）ItwasonthemorningofMay1stthatImetmyfriendattheairport.

Question

怎样选择判断用that而不能用when（强调句和定语从句）
It was on the morning of May 1st when I met my friend at the airport.（ when为什么错?）
It was on the morning of May 1st that I met my friend at the airport.

Answer 1

判断的依据是：将It was (is)...that...同时去掉,句中不缺省成分,则为强调句,否则有可能是定语从句或其他从句,要看具体问题进行分析.
该题中,如果把It was (is)...和所填部分去掉就形成了：“ On the morning of May 1st I met my friend at the airport." 或更通俗一点：“I met my friend at the airport on the morning of May 1st." 因此,其是一个针对时间状语进行强调的句子,因此只能填that(强调结构中的必要部分）而不能填when.