NCE2 lesson58 中 a useful source of income为什么用a 而不用an?
NCE2 lesson58 中 a useful source of income为什么用a 而不用an?
he said that the tree is a useful source of income.请问为什么是is
he has ponted out that tree is a useful source of income
为什么unusual前用a而useful前用an
Tour local library is a useful source of information
useful前面用an还是a?为什么?
He was pointed out that it's a source of income.He's________
he has pointed out that it's a source of income .he's ( ) th
he has pointed out that it's a source of income.He's this to
____(tourist) is a major source of income for the island cou
为什么useful前有时用a(a useful book),有时用an(an useful animal)啊
英语中的hour前面为什么用an,而不用a?