(1)  initially  adv.最初;开始 (英文解释：Initially means soon after the beginning of a process or situation, rather than in the middle or at the end of it.)

 Forecasters say the gales may not be as bad as they initially predicted.预报员说大风也许不像他们起初预报的那么猛烈。

 Initially, they were wary of Simon.  开始时他们对西蒙小心提防。

Initially, the system worked well.开始时系统运转良好。

The death toll was initially reported at around 250, but was later revised to 300.最初报道死亡人数约250，后修订为300。

(2) previously   adv.先前；以前 (英文解释：Previously means at some time before the period that you are talking about.）

 Guyana's railways were previously owned by private companies.圭亚那的铁路以前是归私有企业所有的。

The contract was awarded to a previously unknown company.合同签给了一个之前并不知名的公司。

(3)primitive  adj. 原始的；远古的；未开化的 (英文解释Primitive means belonging to a society in which people live in a very simple way, usually without industries or a writing system.)

Primitive humans needed to be able to react like this to escape from dangerous animals...  

原始人必须要能作出这样的反应以逃避危险的动物。

(4)primary  adj.（教育）初级的，初等的，小学的,首要的；主要的(英文解释Primary education is given to pupils between the ages of 5 and 11.)

Britain did not introduce compulsory primary education until 1880.直到1880年，英国才开始实行初等义务教育。

Ninety-nine per cent of primary pupils now have hands-on experience of computers. 现在，99%的小学生都亲手操作过电脑。

 That's the primary reason the company's share price has held up so well.这是公司股票价格一直居高不下的主要原因。

 I don't think young people's primary aim in life is to get drunk.我觉得年轻人生活的主要目标并不是一醉方休。