单选题 .  Questions refer to the following report.
    Beta Test 459TIB > Provide Feedback > Bug Report
    Category: Supplies (ink)
    Severity: Moderate
    Frequency: Sometimes
    Summary: Printer cartridge is stuck
    Description Details: When the printer has been idle     7    longer than three hours, the LCD shows an error message reading "There's been a paper jam and now the ink cartridge is stuck!     8    the printer and clear the jam Press OK to continue," There is, however, no paper jam, and pressing OK does not resolve the issue.
    Workaround (if any): The     9    way to fix the problem is to restart the machine.
    Comments: I've e-mailed Jonas (ext. 445) about this, since he's using the same machine at his desk.7. 
【正确答案】 B
【答案解析】 选项A错误,when和if不能出现在同一句中。选项B正确,介词for用在一段时间之前。选项C错误,此处不需要连词or。选项D混用了搭配last longer than+一段时间。