1)it‘s a good idea to write an e-mial to each other.(改为同义句)
( To ) ( write )an e-mial to each other ( is ) a good idea
(2)he thinks his teacher will give him the best advice for learning english.
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( Who)(do)(you )think will give him the best advice for learning english?
(3)每天用英语会话很有帮助:it's helpful ( to )(have )(a ) (conversation )in english every day