单项选择题
It is（）for all motorcyclists to wear helmets according to the new regulation.
A.optionalB.compulsoryC.voluntaryD.secondary
单项选择题 It is important to（）strict restrictions on publishing writings nowadays.
单项选择题 The deeper you go into the novel，the more you begin to understand and（）with the characters.
单项选择题 The police made an （）to the public to remain calm.
