effortful
adj. 需要努力的；显示努力的；充满努力的
例句
Inferential activity is likely only when consumers are motivated and able to engage in effortful cognitive processes.
只有当消费者被激励并能够经历费力的认知过程时，推理活动才可能发生。
This structured knowledge is built by years of effortful study.
结构化知识非历经数年苦功不可得。
It takes about ten years of effortful study to become an expert
成为一名专家=十年的时间+刻苦学习
