词汇	casing seat
释义	casing seat 套管承托环
随便看	optional interrupt Optional isolation and polarity-reversal relays optional item optional items optionalities optionality optionality for segmented transport optionality of issuing optionalize optional joint stereo coding method Optional Judgment Optional keyboard and display unit optional label optional lectures for nature science optional legal tender optional length specification optional lessons optional library of program optional list optional local peripheral optional local peripheral circuit optional location optional lot size optionally Optionally Piloted Vehicle