They tested at 4 station ( Củ Chi,

They tested at 4 station ( Củ Chi, Cần Thơ, Bình Tân, Nha Trang)
But they classify the impurity by naked eyes without any tools.

Kết quả (Anh) 1:

They tested at 4 station (Cu Chi, can tho, Binh Tan district, Nha Trang)But they classify the impurity by naked eyes without any tools.

Kết quả (Anh) 2:

They tested at 4 station (Cu Chi, Can Tho, Binh Tan, Nha Trang)
But chúng classify the impurity by naked eyes without any tools.

Kết quả (Anh) 3:

They were tested in 4 stations (potatoes, Can Tho, ISun, que page)But their classify impurity is made by naked eyes without any tools.