At first, thanks all Ranchers. With you, studying becomes enjoying. Without you, I can't go to test center with full confidence.
After test, feel that passing the exam isn't too difficult if you study HF book well. But if you want to get a good score above 90%, you really need study the spec and do the mock exam. I purchased both mock exams. Personally like Whizlabs' mock exam. Its explanation is better than JWebPlus.