We should ___________ (感激) everything our parents have done for us.
Fresh fruit and vegetables c__________ plenty of vitamin C.
With he help of his friends, he finally s________ the problem.
The law needs to be __________ (简化)
We will all have a course in __________ (古代的) history this term.
The head of the large company has many ____________ (职责，责任)
