英文授之以鱼不如:It's 3 years since I saw him last time. 中的it's 能否换成has been?

It's 3 years since I saw him last time. 中的it's 能否换成has been? It's 5 years since I worked there.怎么翻译？ It is written in the book that Thomas Edison ____the world's leading inventor over sixty years. It's Sunday It's ( ) It's dele It's a r_______jaket It's All Vain it's gril 是什么意思？ It's time for