Day 01 - 1

* vulnerable : weak or easy to hurt physically or mentally (상처입기 쉬운, 공격받기 쉬운, 취약한)

  - likely to be hurt, susceptible, weak, precarious

  - vulnerable to infection / vulnerable to cold(flu) / vulnerable to illness / vulnerable to external factors / vulnerable to oil price fluctuations / vulnerable subject

  - Certain people have nervous systems particularly vulnerable to dry winds.

  - Lack of employment outside the home tends to make women more vulnerable to depression.

* mandatory : required or commanded by a law or authority (강제의, 의무의, 필수의)

  - compulsory, obligatory, required, prescribed

  - mandate

  - compulsive / compulsory / obligatory / mandatory / coercive / forceful / peremptory / imperative / arm-twisting

  - In most countries it is mandatory for drivers to fasten their seat belts while driving.

  - Membership in the labor union is mandatory for everyone wanting to work here.

* depend : to trust and need someone / to be directly affected or decided by someone or something

             (의지하다, 의존하다, 신뢰하다, ~에 달려있다, ~에 좌우되다)

  - count on, turn to, rely on, fall back on, be dependent on, be contingent on, be up to, hinge on

  - dependable (undependable), dependent (independent), dependence (independence)

  - be dependent on, be contingent on . hinge on, be up to

  - count on, rely on, fall back on, turn to

  - The value of the evidence depends on its authenticity

  - Unlike in the past, parents can no longer depend on their children in their later years.

  - The amount Kate earned was dependent on how much she sold.

* lucrative : producing a lot of money or a profit (이익이 있는, 수지맞는, 유리한)

  - profitable, well-paying

  - lucre : 이익, 금전적 보수, 벌이

  - profitable (unprofitable), profit, net profit, profiteer

  - profit and loss, sell something at a loss, sell something at a profit, sell something at cost

  - Trying wouldn't do any harm.

  - Recently, CD piracy has become a lucrative business

  - The oldest brother now has a very lucrative position