Generally speaking, the similar Chinese words are difficult for Chinese language learners distinguish. Several groups of such words will be illustrated to show the learners how to tell them apart. The first group of words that the foreigners who learn Mandarin in China should know are机动and灵活. As an adjective, the former one indicates to make proper changes according to the actual situations. It is often used in the aspects of time, manual power and funds. You may often hear Chinese people say 机动处理 and 机动时间.

However, the word 灵活 carries the meaning of being flexible and not limited in the fixed models such as 动作灵活 and 头脑灵活. Before you use this word when you learn to speak Chinese, you should know it has a wider range of application than the former one. Except for the aspects of time, manual power and funds, it is proper in the fields of tactics, guiding principles, policies, thoughts and handling. For example, 对课文中的句型不能死记硬背，要根据情况，灵活运用.

激发and激励is another group of similar verbs you should know. When we use 激发, we usually mean to stimulate somebody to exert oneself like 激发群众的积极性. The objects are usually the abstract thing like initiative, passion and courage. However, the latter one carries the meaning of encouraging somebody. For instance, 老师激励大家要再接再厉. You should know the objects can be both the abstract thing and specific person.

When we intend to express something is fierce, we have three options, 激烈, 剧烈 and 猛烈. Both 激烈 and 剧烈can be applied to describe the wars, fights and campaigns. The former emphasizes both sides are so fierce that reach a very high degree and often used for debate, argumentation, competition and fight. When you come to learn Chinese language in China, you should know 剧烈 is often for the strong changes or stimulate of property of medicines or pain. And 猛烈 is for the heavy things such as artillery fire and storms and rains. You can make a comparison among 斗争激烈、剧烈的疼痛 and 猛烈的炮火.