請教一題文法題!!

[pjacky]

1.People do not become aware (that) health is above everything until they lose it.
2.People do not become aware (of what) health means to them until they lose it.
3.It is only in recent years that people have become aware (of what) a clean environment means to us human beings.
請幫我比較一下這三句的 aware 後面什麼時候要用that 及of what 謝謝!!

[jinaxiu]

只要是of what的一定都是沒有明顯寫出受詞的，我不知道用"受詞"講這算不算對囉..
但是第一句的語意確切是有明顯表達"人們在失去健康後才會察覺到健康至上"

第二句 health means to them >>> is what?
"人們在失去健康後才察覺健康對於他們的意義(為何)"

第三句 clean enviroment means to them >>> is what?
"最近幾年，人們在失去健康後才察覺乾淨的環境對於他們的意義(為何)"

[pjacky]

謝謝你的講解!!