Mrs.Maria, you'd better to renew your passport before you apply for Chinese visa. A passport with at least 6 months left validity is required. If you don't want to renew it, you have to apply for Chinese visa at a time when your passport is still valid for 6 months, in May or so, the single entry tourist visa is generally valid for 3 months from the date of issurance. If you obtain a single entry visa in May, you can still use it to enter China in July, I'm not sure it is still valid in August. Please pay attention to the validity of your passport and Chinese visa.