1. 一年一次的；每年的
    Annual events happen once every year.

annual的近义词

    e.g. ...the annual conference of Britain's trade union movement...
           英国工会运动的年会
    e.g. In its annual report, UNICEF says at least 40,000 children die every day.
           在其年度报告中，联合国儿童基金会称每天至少有4万名儿童死亡。

2. 年度的;全年的
    Annual quantities or rates relate to a period of one year.

    e.g. Annual costs, tuition and fees, £6,600...
           每年的花销、学费和各项杂费6,600英镑。
    e.g. The electronic and printing unit has annual sales of about $80 million.
           电子印刷部门每年销售额约为8,000万美元。

3. 年刊;年报;年鉴
    An annual is a book or magazine that is published once a year.

    e.g. I looked for Wyman's picture in my high-school annual...
           我在中学年刊中寻找怀曼的照片。
    e.g. He tried the various almanacs, annuals and gazettes which were held in the library.
           他试着在图书馆里找过各种历书、年鉴和报纸。

4. 一年生植物
    An annual is a plant that grows and dies within one year.

    e.g. The simplest way to deal with these hardy annuals is to sow them where they are to flower.
           处理这些一年生耐寒植物最简单的办法是将他们种在能开花的地方。