您要查找的是不是：
- N選X系統XooN
- 備選optional
- 報警系統panalarm
- 備選方案alternative (Alt.)
- 運輸系統belt line
- V+X+N（L）V+X+N(L)
- 選股select stocks
- 安全系統security system
- 我們用x表示一個(gè)未知數。We use x as the symbol for an unknown quantity.
- 幫助系統help system
- 再選reelection
- 照明系統illuminating system
- 備選者choice
- y 2 和x n 中，2和n為上標。In y2 and xn,2 and n are superscripts.
- 保障系統safeguards system
- 他們被選去探路。They were chosen to scout the trail.
- 他們在設計道路系統。They are devising a road system.
- 精挑細選choose
- 折射率n(x)在波導截面內是逐漸變化的。The refractive index n(X) varies gradually over the cross-section of the guide.
- 電路與系統Circuits and Systems
