摘要：The abacus in the sixth century by Chinese people .
网址：http://m.1010jiajiao.com/timu3_id_2865810[举报]
--When _____ the abacus _____? -- In the sixth century by the Chinese people.
| A．is, invented | B．did, invent | C．was, invented | D．does, invent |
--When _____ the abacus _____? -- In the sixth century by the Chinese people.
|
A．is, invented |
B．did, invent |
C．was, invented |
D．does, invent |
查看习题详情和答案>>