Pardon = (formal) forgive; the act of excusing a mistake: ‘I’m sure they will pardon the occasional mistake.’

Excuse = give someone permission to stay away from school, work etc., or leave a classroom, meeting etc.: ‘Can I be excused from swimming today please?

I beg your pardon is used (1) to apologize to a stranger because you have bumped into them by accident, sat in their seat by mistake, etc.: ‘I beg your pardon. I didn’t know the table was reserved.’ (2) to politely ask someone to repeat what they have said: ‘Does this bus go to Marble Arch?’ ‘I beg your pardon?’ (3) when someone has said something that makes you feel surprised, shocked, angry etc.: ‘Who’s that woman with long hair?’ ‘I beg your pardon! That happens to be my wife.’

Painful = (1) causing physical or psychological pain: ‘The finger I trapped in the door is still very painful.’ ‘The child wriggled free and gave me a painful kick on the ankle.’ ‘His mischievous behavior brought back lot of painful memories.’(2) causing misery, pain or distress: ‘The painful process of treatment is going on.’ (3) exceptionally bad or displeasing: ‘This movie was painful to watch.’

Overdue= (1) (of payment) past due; being unpaid by the assigned date or at the scheduled time: ‘The electric bill was two months overdue.’ ‘An overdue installment’

Be/become overdue is used of payments, library books, video films that you have rented etc.: ‘Even if the books are only one day overdue, you still have to pay a fine.’

Expire is used of a license, contract, membership card, etc.: ‘I wanted to pay by visa, but my card has expired.’ ‘I suddenly realized that my driving license had expired.’

Outdoor (WITHOUT s) is an adjective. Outdoor = located, suited for, or taking place in the open air: ‘He enjoys the outdoor life.’ ‘There are many outdoor activities in and around Coimbra.’

Outdoors (WITH s) is an adverb. Outdoors = outside a building: ‘He likes to work outdoors.’

Outside = when you mean ‘away from’, use (get/go) out of (NOT outside): ‘It does you good to get out of the city now and again.’ ‘Without a passport, he would never have been able to get out of the country.’

In British English, outside is not used with of: ‘You aren’t allowed to park outside the bank.’

Originate = (1) come into existence; take on form or shape: ‘The practice of Sati originated during ancient Ages.’ (2) to give rise to; initiate: ‘The policy was originated by the previous administration.’ (3) to create something new: ‘Darwin originated the theory of evolution.’

Originate is used in connection with things, ideas, customs etc. (NOT people): ‘No one really knows how the solar system originated.’

If you are born in and/or grow up in a particular place, town, country etc., you come from that place: ‘Where does Agneta come from- Sweden or Norway?’

Oral = (1) using speech rather than writing: ‘Always go for a written agreement in business than relying on an oral agreement.’ ‘In the oral examination, she was asked to recite the name of all presidents.’ (2)  of or relating to mouth: ‘He has undergone an oral surgery.’ ‘She practices good oral hygiene by brushing her teeth at least twice a day.’

Both the words Spoken and Oral can be used to refer to language skills and the communication of information. However, oral is slightly more technical than spoken. The use of oral to mean ‘spoken’ is restricted to certain technical phrases used in education: ‘Oral skills’, ‘An oral examination’.

Use opposite and the opposite of only when you mean that two things are altogether different in nature, quality, or significance: ‘I thought that the medicine would make him sleepy, but it had the opposite effect.’ ‘The opposite of long is short.’ ‘The two men went off in opposite directions.’ (= one went to the left and one to the right)

To describe people’s opinions, life styles, ways of thinking etc., the usual word is different: ‘These two schools of thought are completely different.’

One thing is opposite another thing (WITHOUT to/of): ‘The nearest bus stop is opposite the bank.’

Operate = (1) direct or control something: ‘Do you know how to operate this machinery?’ (2) perform surgery on (medicine): ‘Have you heard what happened to the last patient he operated on?’ (3) to perform a function or work: ‘ The motor operates smoothly.’ ‘The camera also operates underwater.’ (4) to be involved in military activities: ‘A militant group  is operating against the government.’

Operation = (1) the state of being in effect or being operative: ‘That law is no longer in operation.’ (2) a planned activity involving many people performing various actions: ‘They planned a rescue operation.’ (3) a medical procedure involving an incision with instruments: ‘My mother is having an operation tomorrow.’ ‘Mr. Barrett is going to have an operation on his back.’

Once = (1) one time only: ‘You have to take this medicine once a day.’ (2) whenever; as soon as: ‘Once it stops raining, we can go out.’ (3) at some indefinite time in the past: ‘She was a very popular actress once.’ (4) used in negative sentences and questions, and after ‘if’ to mean ‘ever’ or ‘at all’: ‘He didn’t once thank me.’ ‘If she once decides to do something, it becomes difficult to change her mind.’