为学校课堂教学或者科学研究，通过信息网络获取资料，可以规避技术措施。
参考答案：对
—You didn't wait for Mr. Smith last night, did you?
—Yes, but we ________. He didn't return home at all.
A．don't have to
B．needn't have
C．didn't need to
D．should have
胎盘早剥的病因是
A．妊娠期高血压疾病B．多次妊娠分娩C．子宫内膜炎D．母儿血型不合E．胎膜早破
