請教大家3個關於英文使用的問題

您好，

1.when & While的用法差異?

考慮使用 while 或 when 時，先釐清時態和事件發生的長短。"When" means "at the moment". "While" means "during the time".

When I left home, my mother gave me some advice I never forgot.
"when" is used with the simple past tense.
"while" is used in the progressive tense.

While in Taiwan, I had learned how to make caramels.
"In Taiwan" is long duration (''待在台灣''的時間比''學習製作焦糖''的時間長), so "while" should be used, not when.

I was watching TV when she called.
"she called" is a short action (also is simple past tense), so "when" should be used, not while.

When you called, he picked up his cell phone.
series of events; immediately after; "when" should be used, not while.

I was studying while he was making dinner.
Both actions were happening at the same time (同時發生、發生時間大約一樣長). Use of "while" is more appropriate.
此外，當談及年齡、或生命中的某個階段時，一般習慣採用''when''。例如：His parents died when he was twelve.When I was a child, we lived in London.
2.although & though的用法差異?基本上，''though'' 和 ''although'' 有著同樣的意思。你可以放 ''though'' 或 ''although'' 在句子開頭，但是 ''although'' 比較常用也較適當。你也可以放 ''though'' 或 ''although'' 在句子中間的任何地方。以下是例外情況： 可以將 ''though'' 放在句子末端，但不能將 ''although'' 放在句子末端。

He's very smart. He's not a genius, though.

可以用as though (mean as if)，不可以用 as although。

He acted as though he were dreaming.

可以用 even though (mean despite the fact that)，不可以用 even although。Even though he was nervous, he gave the speech without a mistake.
3.這句子為何需要[out]這個單字?Other businessmen thought him crazy to build out in the country, but Hershey knew what he was doing.這裡的 out 是說 out in the country，意思是 away from the city，其他生意人認為他把巧克力工廠蓋在鄉下(遠離城市)是一件不智之舉 (因為不合乎利益效應)，可是 Hershey 很清楚他自己的所作所為 (他很清楚自己在做什麼，也知道他要的是什麼，因為工廠蓋在那邊可以就近取得農場的新鮮牛奶)。
希望有幫到您的忙。

1. When vs While
大部份時間通用, 但 While 有在某段期間內正在進行的意思
故短暫時間的動作不使用 While

2. Although vs Though
大部份時間也通用, 但 Although 對比的語氣比較強
Though 有時可用在同時進行的一般接續, 兩件事同時為正, 但互無明確相剋關係時

3. Build-out 本身是一個詞彙, 算是開發/建立. 這邊是在 build out 什麼東西要看前後文.