网站上说：
http://www.cic.gc.ca/english/citizen/howto-e.html
You must have lived here for at least three years
You must have lived in Canada for at least three years out of the four years right before the day you apply. For example, if you are applying for citizenship on 1 June 1997, we will count back to 1 June 1993. The time you spent in Canada BEFORE you became a resident will be counted as half time only if it happened within these four years. All the time you lived in Canada after you became a permanent resident counts as full time. If you came to Canada on a visa (for example on a student or work visa) before becoming a permanent resident, you may call the Call Centre (see below for the numbers) to find out when you can apply for citizenship.
还是老话，下载申请表格，在cit0002e.pdf, page15,上面有详细的计算，内容太多
http://www.cic.gc.ca/english/citizen/howto-e.html
You must have lived here for at least three years
You must have lived in Canada for at least three years out of the four years right before the day you apply. For example, if you are applying for citizenship on 1 June 1997, we will count back to 1 June 1993. The time you spent in Canada BEFORE you became a resident will be counted as half time only if it happened within these four years. All the time you lived in Canada after you became a permanent resident counts as full time. If you came to Canada on a visa (for example on a student or work visa) before becoming a permanent resident, you may call the Call Centre (see below for the numbers) to find out when you can apply for citizenship.
还是老话，下载申请表格，在cit0002e.pdf, page15,上面有详细的计算，内容太多