题干

某施工队挖掘一条长90米的隧道,开工后每天比原计划多挖1米,结果提前3天完成任务,原计划每天挖多少米?若设原计划每天挖x米,则依题意列出正确的方程为(   )

A:90x90x1 =3

B:90x190x=3

C:90x90x+1=3

D:90x+190x=3

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答案(点此获取答案解析)

C

同类题4

   Some students, parents and teachers in Shanghai were surveyed last month. According to the result of the survey, the generation gap(代沟) between students and parents as well as teachers is becoming wider. Here is what they said.
Voice of the students:
   “Our parents hold too high expectations which put us under lots of pressure. They care too much about our lives and studies,” one student said.
   “It's impolite that some students’ parents read their children's diaries without permission!” one student said angrily.
   “Some of our teachers are so serious that we can't make friends with them at all,” another student said sadly.
Voice of the parents:
   One mother said, “After school, my daughter usually locks herself into her room and spends lots of time talking with others on the phone. And I can't stand her clothes and hairstyle!”
   “I thought my son was doing very well in his studies. I didn't realize I was being cheated by him until I got a call from his teacher,” said a father.
Voice of the teachers:
   An English teacher said, “Today, the role of the teacher is to put knowledge into students' brains. The power of teachers has kept students away from them.”
   “Some parents pay too much attention to their children's grades instead of creating a lively and colorful environment at home,” another teacher said.
   “In the past, teachers and students often played games together or talked with each other. Today, only studies and grades are talked about,” said a teacher. “A school should be a place where students can learn not only knowledge, but also how to face failure and frustration bravely enough.