题目

—How did it ______ that you made such a silly mistake? —I myself haven’t figured it out yet. A．bring about      B．come about C．come across      D．come on 答案：B怎样简便怎样算。 5.02－3.5＋0.98 2.88＋2.3＋4.7 36.78－21.5－13.28