Hvt
半值厚度辐射屏蔽
🗣️ 情景例句
Learning to express oneself well in an important part of education.
学会把意思表达清楚是受教育的一个重要方面。
Nice to see you, my old friend.
真高兴见到你，我的老朋友。
it is not always safe by the time it reaches the tap.
等水到达龙头时就不一定总是安全的了。