Maria has ____trouble ___math, so she often asks her math teacher for help.

I really like the photo of my family ____my sister took in the city park last year.

The doctor the farmer sent his son is well-known in the field.

___ is well-known to all is that the 2010 Shanghai World Expo has been brought to an end.

oughshe sometimes loses her temper, her students like her no less— That’s it _____ , she is really a good teacher