单项选择题
Most parents encourage their children to take an active part in social events,（）those events do not interfere with their studies.
A.lest B.though C.unless D.provided
单项选择题 Dogs are often praised for their（）they almost never abandon their masters.
单项选择题 We（）the cook because her cooking was so poor.
单项选择题 Preliminary estimation puts the figure at around $110 billion,（）the $160 billion the President is struggling to get through the Congress.
