我想問這句 英文有什麼文法和意思?

Question

Mrs Mary had nearly twice the usual amount of neck, which came in very useful as she spent
so much of her time craning over garden fences, spying on the neighbours. 此句有使用何種文法呢，另外came in是come in的過去式吧，在這是指什麼意思呢

Answer 1

Mrs Mary had nearly twice the usual amount of neck, which came
in very useful as she spent so much of her time craning over garden
fences, spying on the neighbours.
瑪莉的脖子大概有一般人的兩倍長, 這個特點在她經常隔著庭院的籬笆引頸窺探鄰居的時候, 非常有用. (A)
瑪莉的脖子大概有一般人的兩倍長. 因為她經常隔著庭院的籬笆引頸窺探鄰居, 所以這個特點非常有用. (B)
which引導一個用來附帶說明的子句, 它可以代表前面整個句子; 把它視為代表neck也可以說得通.
come in useful: 很有用(come in 是"發揮功能"的意思).
as在這個句子既可以解為"when"(A), 也可以看成是"because"(B). 是從屬連接詞.
動詞spend(過去式spent)後面接動名詞(Ving): 花時間做(某事).
crane over garden fences: 隔著庭院的籬笆伸出脖子.
spy on: 窺探.