Fill in the blanks with the correct prepositions in the brackets
(i) He is working on his homework……………… (for/during/at/in) the moment.
(ii) I am glad to receive your letter…………… (in/after/by) such a long time.
(iii) Sonalika has been playing…………………… (since/for/after) two hours.
(iv) Rajesh has to deliver these goods …………………. (since, by, during) 30th April.