问题
选择题
| —When _________ the abacus _________? —In the sixth century by the Chinese people. |
A. is; invented B. did; invent C. was; invented D. does; invent |
答案
答案：C
搜题请搜索小程序“爱下问搜题”
| —When _________ the abacus _________? —In the sixth century by the Chinese people. |
A. is; invented B. did; invent C. was; invented D. does; invent |
答案：C