根据对话填写数字。

A: Hello, Amy. How many apples are there on the table?

B: Twelve. Hi, Sarah. How many flowers are there?

A: Twenty. I have six oranges. How many ants are there on the floor?

B: Wow! There are thirty.

1.  _______________

2.  _______________

3.  _______________

4.  _______________

按照“到达打基础、（）、中转保畅通”的列车技术作业要求，强化到达作业发现故障和处理故障能力，为始发作业打好列车技术质量基础，确保始发作业和中转作业中不因到达作业漏检漏修影响运输秩序和运输安全

A、简化看始发

B、确保看始发

C、强化看始发

D、始发看重点