下列各选项中，对文中相关内容的解说不正确的一项是（ ）

Is that ________ ruler No, it’s _________ orange.

Why not come and join us in the game?—__________, but I must meet Mr. Smith at his office now.

the unreasonable individual income ­_______,the gap between the rich and poor has become an outstanding issue.

By the year 2020 scientists _____ a lot of research on AIDS