nothing but some flowers____(is \are)in the basket.

nothing but some flowers____(is \are)in the basket.
nothing but some flowers____(is \are)in the basket.

nothing but some flowers____(is \are)in the basket.
应该填的是is.
这里用谓语动词单数形式,因为but是介词,构成一个介词短语来修饰前面的不定代词,前面的不定代词才能充当主语 .
即应该把nothing当做主语.

nothing but some flowers__is__(is \are)in the basket.