题目

 — Does he know how to work out the problem? — Yes, he has ________ a good idea to solve it.       A. come up with        B. caught up with        C. kept up with  D. put up with 答案：A（1）一个七位数，它的最高位是(　　)位，最低位是(　　)位；（2）最高位是千万位的数是(　　)位数．