Engage

(i) Carry out or participate in an activity; be involved in: ‘They engaged in a discussion’ (ii) Consume all of one's attention or time: ‘Her interest in books engages her completely.’ (iii) Start in a job or pay to do a particular piece of work: ‘They engaged two new secretaries in the department.’(iv) Be/get engaged: ‘When did you get engaged?’ ‘We were engaged for almost a year before we got married.’

Engaged

(i)Be/get engaged to sb: ‘When we first met, she was already engaged to an airline pilot.’ (ii) Having one's attention, mind or energy occupied: ‘He is deeply engaged in conversation.’ (iii) Reserved in advance: ‘Three or four of these highway lanes must be engaged for passenger cars only’. (iv) (Of facilities such as telephones) unavailable for use by anyone else or indicating unavailability: ‘His telephone numbers are always engaged.’

Emergency

As noun = (i) A sudden unforeseen crisis (usually involving danger) that requires immediate action: ‘Always try to stay calm in an emergency.’ ‘She never knew what to do in an emergency.’(ii) A state in which martial law applies: ‘The president declared a state of emergency.’

Elect

Elect = Select (someone) by a vote for an office or membership: ‘The committee has elected a new chairman.’

Choose = decide which one you want: ‘We choose Sri Lanka because we hadn’t been there before.’

Economics

(i)A branch of social science that deals with the production, distribution and consumption of goods and services and their management or the study of how money is earned, spent, and controlled within the country: ‘He is in his second year at oxford, studying economics.’ (ii) The financial aspect of something: ‘The economics of dairy farming.’

Efficient

(i) Being effective without wasting time, effort or expense: ‘Efficient engines save petrol.’

(ii) Able to accomplish a purpose; functioning effectively ‘He is an efficient production manager.’

Each other

Each other (reciprocal pronoun) has no plural form: ‘We've been writing letters to each other for the last two years.’ ‘We help each other through hard times.’

Dust

Small dry particles: very small dry particles of a substance such as sand or coal, either in the form of a deposit or a cloud.

Dust is an uncountable noun: ‘The house hadn’t been lived in for a long time and the furniture was covered in dust.’