He was employed for a two year period on a trial basis.他受雇试用两年。He was hired for a three month period on a trial basis.他受雇试用三个月。The new system will be introduced on a trial basis.这个新系统将被引入试用。I'm using the product on a trial basis. 我正在试用这款产品。You can have it for a fortnight on a trial basis.你可以试用它两星期。