Both ‘Until’ and ‘Unless’ are generally used as conjunctions to connect the sentences in English. Note: Both of these might also be used as prepositions, but we are learning the use of connectors or conjunctions. Look at the difference:
Use of Unless
Unless is used, when the condition is set, and is already considered negative form in connectors, so don’t use ‘Not’ with Unless sentence. Here are some examples:
# I shall not lend you money unless you give me gold.
# He will not come to your home unless you go to his.
# Bank will not provide you loan unless you show them your original identities.
# He will not trust you unless you prove yourself.
Until is used up to the particular time, and is already considered negative form in connectors, so don’t use ‘Not’ with Until sentence. Here are some examples:
# Wait here until I come back.
# Until I complete the home-work please don’t switch-on the T.V.
# Until the train comes don’t board.
# They did not come until the meeting was half over.
# He read until his guests arrived.