This is ( )empty bottle.But it is ( )useful one.A a ;a B an; a C an;the D a;an

This is ( )empty bottle.But it is ( )useful one.A a ;a B an; a C an;the D a;an

B empty 元音开头 用an

B

B
empty ['ɛmptɪ]
useful ['jusfəl]

B