notuntil.heardfrom 　　until用于强调时间的强调句型： 　　Itis(was)notuntil…that"直到…才",此时不可以用till代替. 　　ItwasnotuntilyesterdaythatIgotyourletter/heardfromyou. 　　直到昨天,我才收到你的来信. 　　强调句型 　　Itis(was)+被强调部分+that(who)+句子其他部分.(当强调的部分是人,且为句子的主语时,才用"who",其余用that.) 　　强调句去掉Itis(was)...that之后还是一个完整的句子. 　　此结构强调的成分仅限于主语,宾语和状语. 　　I原句：Myfatherdidtheexperimentinthelabyesterdayevening. 　　强调主语：Itwasmyfatherwhodidtheexperimentinthelabyesterdayevening. 　　强调宾语：Itwastheexperimentthatmyfatherdidinthelabyesterdayevening. 　　强调时间：Itwasyesterdayeveningthatmyfatherdidtheexperimentinthelab.(注意不用when) 　　强调地点：Itwasinthelabthatmyfatherdidtheexperimentyesterdayevening.