Payment terms: By L/C at sight or T/T advance是什么意思?

Payment terms: By L/C at sight or T/T advance是什么意思? L/C at sight or T/T in advance Payment with L/C on sight or T/T in advance. 请问payment terms:L/C at sight T/T, L/C at sight 的 at sight 是什么意思? Payment Terms - 100% LC at sight (or) 30% advance balance ag 25% for advance, 50% for L/C at Sight and rest 25% payment b 25% for advance,50% for L/C at Sight and rest 25% payment be 请翻译下“ Terms of payment:%100 Irrevocable L/C at sight” 30% Deposit by T/T,the balance paid by L/C at sight 什么叫Irrevocable L/C at sight or T/T upon receive the copy of 我是外贸新手.alance T/T or L/C at sight before delivery"!