重點講解：
1. break down （使）（物質）分解；
Over time, the protein in the eggshell breaks down into its constituent amino acids.
時間久了，蛋殼中的蛋白質就會分解為其構成成分氨基酸Cv;b%NBaeCp1HknQM)qT。
2. at least 至少，起碼；
Success was assured and, at least to start with, the system operated smoothly.
成功有保證了，至少該系統一開始運行得挺順利~N,R3BG1.BCvzN。
3. clean out 徹底清理(櫥柜、房間、容器等)；把…打掃干凈；
Mr. Wall asked if I would help him clean out the bins.
沃爾先生問我能不能幫他把各個箱子徹底清理一遍36phHPi6)GWB。
4. come into contact with 接觸；遇見；
Common sense tells us that most fuels can burn only when they come into contact with air.
常識告訴我們，大多數燃料只有接觸空氣時才能燃燒4b^%Y%B!m;!mzk。