1. The money is invested principally in oil.
    资金主要用于石油方面。

1. 主要地：prime 最初、青春;主要的、最初的 | principally 主要地 | probability 可能性、或然性

2. 主要,大抵：primitive 原始的 | principally 主要,大抵 | printer 打印机

3. 侧重居首要地位：primarily 侧重基本地,首要地. | principally 侧重居首要地位. | generally 通常强调普遍性.

4.

4. 通常的;照惯例的：a.流行的;盛行的 customary | a.通常的;照惯例的 principally | ad.主要,大抵 decorative

1. 主要地；首要地；最重要地
    Principally means more than anything else.

    e.g. This is principally because the major export markets are slowing...
           这主要是因为主要出口市场发展缓慢。
    e.g. Embryonic development seems to be controlled principally by a very small number of master genes.
           胚胎发育似乎主要受制于少数主导基因。

1. for the most part

    e.g. he is mainly interested in butterflies

    Synonym: chieflyprimarilymainlyin the main