The purpose of this research was to develop English exercises based 
on local curriculum  and test its effectiveness in teaching Mathayom 3 students. 
In addition, the change in English performance of students following the 
exercises were investigated along with their opinions toward the exercises.

The sample consisted of 26 students in Nongkae School under the Jurisdiction 
of the Phetchaburi Provincial Primary Education. The students studied the 10 
units of exercises over 20 class sessions during the 10 weeks of the first 
academic semester of 2001.

The students were given a pretest before the exercises were administered. 
At the conclusion of the 10 units, the students were given a posttest. The data 
from the pretest and posttest were analyzed using the t-test in order to assess 
any change in the students’ English performance. In addition, practice exercises 
were given to the students after the completion of each unit. The average of the 
10 practice exercise scores was compared with the posttest scores in order to 
determine the effectiveness of the English exercises. A questionnaire was given 
to the students following the 10 units. The mean and standard deviation of the 
questionnaire scores were used to assess the students’ opinions toward the English 
exercises.

The findings revealed that :

1. The effectiveness of the English exercises was 83.58 and 84.42 percent for 
the practice exercises and posttest, respectively. This means that the English 
exercises were highly effective.

2. The students’ English performance after using the 10 unit exercises was 
significantly higher at the 0.05 level.

3. The students’ opinions toward the 10 unit English exercises were highly positive.