necessary可数吗

　　双语例句：

　　Hospital admission is not necessary in most cases.

　　大多数情况下，病人无须住院。

　　The report concluded that no substantive changes were necessary.

　　报告的结论是，无须作任何重大变更。

　　It might be necessary to make a few slight modifications to the design.

　　也许有必要对这个设计稍作几处修改。

　　We are willing to make any concessions necessary to this end.

　　为达到此目的我们愿作出任何必要的`让步。

　　We are still looking for someone who combines all the necessary qualities.

　　我们仍在寻觅兼备所有必要才能的人选。