高一英文觀念問題

(1) Coconut-water IVs were also reported to have been used during World War II...
為什麼是用"have been used" ; instead, "had been used"?

To-infinitive 後面的動詞是 base form of the verb
只有 to have, 不能 to had, 甚至不能 to has,
She wanted to have a boyfriend.
She wanted to had a boyfriend 是錯

所以用 "have been used" instead, "had been used"
你句子的 have 是 auxiliary verb (助動詞)

He said, "I have done this." ~ direct speech
He said that he had done that. ~ reported speech

(2) Ladybugs normally live one year, but some can live up to two or three years.
其中的"live up to"該怎麼翻譯?

live up to 應該分開兩個部分解釋
live = 活, 生存
up to = 一直到
"live up to" = 活到

"live up to" 在這個句子不是 verbal phrase,

(3)a flock of / a host of 前者當"群" 後著當"很多"時, of 後面是否都接可數名詞?

是可數名詞, 但要 plural (複數), 因為多過一個
flock 和 host 是 group noun
a flock of (animals), a flock of birds,
a flock of sheep, (sheep 單數複數都是 sheep)
a flock of tourists, a flock of children

a host of (people, things),
a host of angels (不是 a host of angles), a host of friends,
a host of possibilities, a host of reasons

(4) He emphasized learning through all the senses and combining pictures and words in the lessons.
為什麼是用"in the lessons" 而不是 "in lessons"

lessons 是 plural (複數) noun. 要用definite article, “the” 或無 article (冠詞)
We don’t use an article when we want to refer to a group or class in general.

Lessons start at 9 o’clock. (普遍的 lessons)
The government fails to learn the lessons of history. (某 lessons)

因為你的句子提到 “combining pictures and words”, 要某 lessons, 因此要用 the 在 lessons 前面. 不是普遍的 lessons

題外:.
Live up to 可做 verbal phrase
Verbal phrase 中的 live 與 “生活, 生存” 是無關.
live up to (something) = 達到,實踐,履行,符合,不辜負 (something)
If something or someone lives up to a particular standard or promise, they do as well as they were expected to, do what they promised etc :

The film has certainly lived up to my expectations.

(1) Coconut-water IVs were also reported to have been used during World War II...
為什麼是用"have been used" ; instead, "had been used"? 因為句子的主要動詞是were reported(指有報告指出coconut-water IV這東西 [註:IV是intravenous靜脈注射的簡稱)，所以要利用to infinite式的句子以方便接連use和coconut-water IV的關係而不用更改以coconut-water IV作為主詞。假如改為直接動詞指cocount-water IV had been used during WWII，全組句便要改為It was also reported that coconut-water IVs had been used during WWII.

(2)Ladybugs normally live one year, but some can live up to two or three years.
其中的"live up to"該怎麼翻譯?
live = 生存/生活up to = 最多/極限(年期)綜合翻譯:甲蟲一般會存活一年，但有些可以活至兩三年之久。或甲蟲一般會存活一年，但有些最長壽命可以是兩至三年。
(3)a flock of / a host of 前者當"群" 後著當"很多"時, of 後面是否都接可數名詞?
後面接的基本都是可數的動物名詞…而且必定是眾數。a flock of pigs (animals).a host of angles.
(4)He emphasized learning through all the senses and combining pictures and words in the lessons.
為什麼是用"in the lessons" 而不是 "in lessons"因為這句正在談論的是那些他在講及的課堂(the lessons he had been talking about)，而不是所有課堂或任何課堂。