Think: to have opinion or belief about sth.

　　翻译为“认为”，通常接宾语从句来表达比较确定的观点。

　　Assume: to think or accept that sth is true but without having proof of it.

　　翻译为“假设、假定”，是否有事实依据是不确定的。

　　Claim: to say sth is true although it has not been proved and other people may not believe it.

　　翻译为“声称”，用这个词往往意味着不赞同紧跟其后的观点，所以很少用作 ‘I claim that…

　　Scientist are claiming a breakthrough in the fight against cancer, but in fact, ….

　　所以 ‘It is claimed that’ 通常翻译为“有报道称。。。”。和‘it is reported that ’的区别在于后者翻译为“据报道”，往往代表着作者赞同报告的内容，

　　Consider: to think about sth carefully, especially in order to make a decision

　　翻译为“考虑”，一般不用作引出观点，看个例子：

　　We are considering buying a new car.