[誤] To learn English well, a great deal of practice is necessary.
[正] To learn English well, one needs to have a great deal of practice.
注:英語中非謂語動詞的邏輯主語要與句子的主語一致,本例句中不定式 to learn English well 的邏輯主語應(yīng)該是“人”,而句子的主語卻是 practice,兩者不相一致,違背了英語習慣,所以必須將句子的主語改為one,并做其它相應(yīng)的調(diào)整。