entering US with B2 and returning to a third country

[badukman]

I am a Chinese citizen. I am going to Canada to pursue my PhD in a university in September this year. I currently hold a US B2 visa. I am planning to enter the US for 2 weeks and then head to Canada. But when I started to book the tickets the airline agency told me that I have to get a return ticket or I will be denied boarding/entry. Is this true? Are there any ways that I can avoid this? Thanks.

[immihelp]

In this case, you are actually "transiting" through the U.S. Therefore, it is OK.

[badukman]

Thanks. But if I fall into the category of "transiting", the time I can stay in US is 3-7 days. Will the immigration officers allow me to stay longer?

[immihelp]

Yes, you can as you have B2 visa and not transit visa.

[badukman]

I see. Thank you very much!