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Can I say,

(a) They are playing (with) a kite.

(b) They embraced each other warmly.

(c) He hailing at the taxi.

(d) The bridge is over the river.

(e) There was a road accident at the traffic light.

(f) Uncle Lim rears some poultry on his farm every day.
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Vincent TeoCan I say,

(a) They are playing with a kite. OR They are playing with kites

(b) They embraced each other warmly. ok

(c) He [is/was] hailing a taxi.

(d) The bridge is over the river. ok

(e) There was a road accident at the traffic light. ok

(f) Uncle Lim rears some poultry on his farm every day. ok; but better without "every day" as "to rear" something implies a period of time.

Comments  
a) they are playing a kite (no preposition)

c) He hailed the taxi or he was hailing the taxi (no preposition and mind the tense you want to use)

All the rest seem to be ok.
 Feebs11's reply was promoted to an answer.