及时, 按时, 准时，准点 When to use and what do they imply?
I'm a bit confused about when to use these words. I know sometimes one can be substitued for another but sometimes changing the word will change the meaning implied.

Can anyone give me some examples to give me a better understanding? (I have had some explanations before in Chinese and while I appreciate the help, I just can't understand some of the explanations so if possible can you use English to explain.

Thank you!

Question

及时,  按时, 准时， 准点 When to use and what do they imply?
I'm a bit confused about when to use these words. I know sometimes one can be substitued for another but sometimes changing the word will change the meaning implied.

Can anyone give me some examples to give me a better understanding? (I have had some explanations before in Chinese and while I appreciate the help, I just can't understand some of the explanations so if possible can you use English to explain.

Thank you!

Answer

及时： 强调事情很重要，千万不能迟到，要准时到达。
 按时, 准时， 准点：这三个词没有多大差别。
其中“准点”强调时间很精确，对时间点很在意。
In a word，  按时, 准时， 准点，之间没有差别。“及时”强调事情的重要性（some thing is important and must in time）
My english is poor.Don't care.

Answer

及时it happens at the moment that  someone hopes it happens, for example,正当我缺钱的时候，他就及时第给我弄来三百块钱。
按时 someone does something at the moment of appointment after making an appointment.for example, 他按时把作业交上来
准时it happens at a second of a minute of a clock according to the time that makes ahead of time, for example, 八点二十一分二十八秒准时点火
准点and 准时 have the same meaning, 点here means o`colck,准时点火，准点点火，all is OK

Answer

There is another thing very important. 
准时 can be an adjective. it is more like punctual. other words are adverb. 
eg. 你很准时 You are very punctual.
准点 is more casual way to say, spoken language, used in chitchat. 
other words more formal.

Answer

及时, 按时, 准时， 准点
及时
  1.timely  ：in time  
 ex.sow in  good time 及时的播种
2.promptly  ： without delay
Get prompt treatment when you are ill. 当你生病的时候，得到及时的治疗
按时 on time /on schedule
 I arrive on time.
准时=准点=按时  Actually there are on difference between those words. You
can  use one of them when you want to express doing thing on time.

Answer

及时means " in time" in English. The other three all mean "on time". The difference is very subtle. Just that 准点 is usually found in train timetables or formal situations.
eg, 火车6点整准点发车。 （The train leaves at 6 o'clock precisely.)

Hope it helps a little.