ខ្ញុំជាអ្នកជឿជាក់ដែលអ្នករាល់គ្នាដឹង ផ្លេកបន្ទោរ rods. When we were in junior high school, the textbook covered it in detail. In our daily life, we often see ផ្លេកបន្ទោរ rods at the top of multi-storey buildings and have the effect of maintaining buildings, but many people have little kno...
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