Nitropo
硝酸钾钠
🗣️ 情景例句
I don't know,
我不知道，
Perseverance is failing nineteen times and succeeding the twentieth.
十九次失败，到第二十次获得成功，这就叫坚持。
and we have to lower into the ground and haul out of the ground great lengths of drill pipe which are rotated by an engine at the top and are fitted with a cutting bit at the bottom.
我们必须把很长的钻杆一节节地钻入地下，然后再从地下拉出来。钻杆顶部安装的发动机带动钻杆旋转，它的底部装有钻头。