when he heard the bell,he ran into the classroom ____?A.just now B.at once C.in a minute D.now
问题描述：
when he heard the bell,he ran into the classroom ____?A.just now B.at once C.in a minute D.now
为神马是B?不是A么?
答
just now意为刚才,是过去世的标志.
at once意为立即,与选题意思相符!