I will write down the phone number ____ I forget

The main objective of a 'conjunction' is- Tell me _ that. It is health _ is wealth. 'Don't go out while it rains' In this sentence 'while is a/an- I will watch while you sleep. এখানে “while শব্দটি- 'He is poor but honest.' _ in this sentence which is conjunction? Look before you leap. The word before used in the sentence is— Give her a telephone number to ring ……… she gets lost. 'He could not win but learnt a lot.' Which part of speech is the word 'but'? Water boils _ you heat it to 100° centigrade.