before表示“在……之前”的意思，強調時間先後關係；
而until表示“直到……才”的意思
在下列情況下，用before不用until。
1.主句這肯定式、終止性謂語動詞，只用before。例：
(1)He fell asleep before I could take off his clothes.
(2)We arrived there before it atarted to rain.
2.主句謂語動詞強調動詞的遲緩性，只用before，常伴有時間段狀語或時間段暗示。例：
(1)It was quite some time before he found the elephant at all.
(2)We had walked a long way before we found some water.
現在回到你的問題：
How long do you think it will take___our product becomes popular with the consumers?
因為有do you think的插入語，說明產品暢銷（product becomes popular）的情況還沒有出現，不確定何時暢銷，所以 take具有遲緩性，所以填
before
before表示“在……之前”的意思，強調時間先後關係；
而until表示“直到……才”的意思
在下列情況下，用before不用until。
1.主句這肯定式、終止性謂語動詞，只用before。例：
(1)He fell asleep before I could take off his clothes.
(2)We arrived there before it atarted to rain.
2.主句謂語動詞強調動詞的遲緩性，只用before，常伴有時間段狀語或時間段暗示。例：
(1)It was quite some time before he found the elephant at all.
(2)We had walked a long way before we found some water.
現在回到你的問題：
How long do you think it will take___our product becomes popular with the consumers?
因為有do you think的插入語，說明產品暢銷（product becomes popular）的情況還沒有出現，不確定何時暢銷，所以 take具有遲緩性，所以填
before