Course work done by

The positive changes in the roles of high school teachers and students
Secondly, not only teachers but also students have to be willing to change their roles in the classroom. As Tran (2012a) states that it is difficult tasks as they are more familiar with traditional methods of teaching and learning and the changes are rather time-consuming. It is true for those who are at high schools as high school teachers and students have to depend heavily on a crowded curriculum with different subjects (Hoang, 2014). However, when they are ready to shift into the new active roles, their innovation pedagogy and even their personal beliefs, PBL can be implemented effectively and successfully (Truong, 2017). Moreover, when the teachers can overcome problems such as school infrastructure,
available resources and time, they can trigger the students’ creativity and enthusiasm in implementing PBL.
Adequate training for high school teachers and students
It is of essence that Vietnamese high school teachers, whose new roles are instructor, facilitator, supervisor and monitor, should be supplied with appropriate training by the MOET and the DOET. Besides, being equipped with adequate skills, teachers should also be supplied with the process of project implementation as well as the ways to evaluate students (Nguyen, 2017). When they have sufficient skills they may train, instruct and help their students if necessary. Teachers should have the comprehension of
students’ basic knowledge and facilitate students learning process by
helping them to combine their basic knowledge and the new one to solve the complicated tasks in real life. Moreover, teachers should plan learning materials and assessment rubric carefully for students. Moreover, it is critical that teachers who implement the project should be experienced to instructing students to do projects. High school students, the center of the learning process, are also well-prepared with basic knowledge and soft skills to implement PBL effectively.