Analysis: According to the meaning of the question, it takes 8 seconds to knock 5 times at 5 o'clock, and there is an interval between each knock. * * * has 5- 1=4 intervals, and the interval time is 8÷4=2 seconds; Knock nine times at 9 o'clock, there are 9- 1=8 intervals, and then multiply by the interval time.

The formula is:

8(5- 1)= 2 (seconds)

2×(9- 1)= 16 (seconds)

A: At 9 o'clock, 16 seconds is over.

Extended data:

Steps of application problems in primary schools

The first step is to examine the questions.

The second step is to judge the quantitative relationship.

The third step is to determine the operation method and sequence.

The fourth step is column calculation, and finally the answer is tested.

To sum up, the essence of solving practical problems is to turn practical problems into mathematical problems first, and then solve practical problems by solving mathematical problems. In this process, the column equation plays a role of connecting the past with the future. Therefore, the column equation is the key to solve the application problem.