2 Wearable technology devices________ over 30% of the company’s total sales three years in a row.
(A)account for
(B)amount to
(C)accumulate for
(D)add up

這裡的account for  是比較特殊的用法，算是只能用英文去理解的…中文有些難說明

Wearable被穿戴的  technology科技 devices裝置  account for (令人滿意的記錄) over (超過) 30% COMPANY'S total sales tree years in a row 連續三年.

=>被穿戴的科技裝置 創下了(令人滿意)的記錄 ，因為這記錄是特別對超過公司的總銷售(連續三年)的30%地創下。

後面over是說明如何創，所以應該是副詞。

account for =>特別對(因為)什麼事蹟 而去 account 創記錄、帳戶來記

所以也有 特別去記錄，做成帳戶==>特別去"解釋說明"的意思。

但這裡不是說解釋說明…是"創"的意思

for 因為某事+ ac再往前 +count計算=>因為某方面再往前計算、記錄。

補充資訊，沒有雖然沒有解釋for (特別對某方面) ac(進一步) count(去計)的解釋。

https://en.oxforddictionaries.com/definition/us/account_for

PHRASAL VERB

• 1Give a satisfactory record of (something, typically money, that one is responsible for).

  Example sentences

  1. 1.1 Provide or serve as a satisfactory explanation or reason for.
     ‘he was brought before the Board to account for his behavior’

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     Synonyms
  2. 1.2 Know the fate or whereabouts of (someone or something), especially after an accident.
     ‘everyone was accounted for after the floods’

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  3. 1.3 Succeed in killing, destroying, or defeating.
     ‘the fifth inning accounted for Lyons, who gave up three back-to-back home runs’

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     Synonyms

• 2Supply or make up (a specified amount or proportion)

  ‘social security accounts for about a third of total public spending’