http://www.cra-arc.gc.ca/tx/bsnss/sm/gsthst-tpstvh/rgstr-eng.html
你在cra注册gst了吗?
you have to charge and remit the GST/HST on your taxable supplies of goods and services. You can claim input tax credits (ITCs) for the GST/HST paid or payable on purchases for these supplies.