It was Christopher Columbus who first p_______ Ametican continent.

It was Christopher Columbus who first p_______ Ametican continent. 句子结构分析,求大神指点：It was 80 years before Christopher Columbus crossed the ...具体如下：It was 80 years before Christopher Columbus crossed the Atlantic ____ Zheng He had sailed to East Africa.A. when B. that C.after Christopher christopher _____was in 1492 that christopher columbus arrives in the new world A.this B.that C.it D.time It was 80 years before Christopher Columbus c rossed the Atlantic ____ Zheng He had sailed t o East Africa.A.when B.that C.after D.since 为什么不选A,就是当郑和下西洋时,比……早八十年,it指代郑和下西洋这件事 It was 80 years before Christopher Columbus crossed the Atlantic _____ Zheng sailed to East AfricaA.when B.that C.after D.since选哪个?为什么不选其他的?It be +时间+连词（when、before、after、since） 这个句型我一直不知道 it was cold yesterday-------------a.so it was b.so was it c.it was so d.was it so Christopher gorham Christopher gorham 1道英语选择哈~Explorer Christopher Columbus landed in America,but he thought he thought he （）the east indiaA.had discovered B.has discovered C.discovered D.was discovering It was very cold yesterday.___________________A So was it B So it was C It so was D Was it so It was _____ he was so young that he c 谁帮我想下英文名 C字母开头长一点好看的.如Christopher. 下面这句英文怎么可能是it is that强调句型,我觉得是形式主语.老师和答案都说这是强调句.It was 80 years before Christopher Cloumbus crossed the Atlantic that Zheng He had sailed to East Africa. 强调句和定语从句的区别我不清楚去掉it is... who/that...确切要怎么去,去掉后要怎么判断例如：It was 80 years before Christopher Colmbus ciossed the Atlantic ˍˍ Zheng He had sailed to East Africa.这个句子要 It was c( )this morning,but it's sunny now In fact,Christopher Columbus used a version of it when he set sail in search of the New World - which caused him some navigational problems,since Ptolemy had calculated wrongly the size of the Atlantic and was unaware that the Pacific Ocean existed.