In Chinese language, only one different character in the words may cause big difference in meaning. For example, the group of words及时、按时and 准时are all related to time but have various meanings. First of all, as an adjective, the word及时carries the same meaning with “in time” in English, meanings to catch up with the proper time or need. For example, some students who learn Chinese in China may often hear 你来得很及时，我正要找你呢.

The word 按时is an adverb which means to follow the specified time, just as the same meaning with “on schedule” in English. You can say 他每天按时出勤，从不晚来早走. If you study in Mandarin learning courses, you may also learn the word 准时 that is similar to this one. Functioned as an adjective, 准时 means the time is just the appointed time. Accordingly, you can say 飞机准时起飞 and 他每天六点准时起床.

Another group of confusing words are 技术 and 技巧. Generally speaking, the former one is the experience, knowledge and technique accumulated in the aspect of labor productivity in long process as well as the general techniques in operation. What you often hear may be 技术革新 and 改进技术. However, 技巧 belongs to a kind of skill, meaning the ability to use certain techniques, mostly in the aspects of art, literature and cultural creation as well as sports. For instance, 他的写作技巧很高超.

You may think the group of words 寂静 and 寂寞 are difficult to distinguish if you meet them when learning inintensive Mandarin course in China. But it is just the opposite. The former one means it is so quiet and there is no sound. It is usually applied to describe the quiet environment. You can say 夜深了，四周一片寂静. However, the word 寂寞 has similar meaning with “lonely”. It describes people feel lonely because of lack of friends or things to do. It belongs to a kind of subjective feeling. For example, 老人很寂寞.