【評論主題】25. If you had helped me then, I __________.(A) might succeed (B) had succeeded (C) might have succe

【評論內容】假設語氣:此題為對於過去事實做假設If ...

【評論主題】29.水中污染物的濃度有時以 ppb 來表示,1ppb 等於下列何質量濃度?(A) 10ng/L (B) 1ng/L (C) 1mg/L (D) 1μg/L

【評論內容】1ppb=1/10*9 換算成濃度單位應★1........