一般来说，下列哪一种疾病的牙龈增生最为严重
A．青春性牙龈炎
B．妊娠性龈炎
C．遗传性牙龈纤维瘤
D．增生性牙龈炎
E．药物性牙龈增生
参考答案：C
根据句意和首宇母提示，补全各小题单词。
小题1:Your poor English needs i____________.
小题2:We should try to learn foreign languages as well as c_________.
小题3:Good eating h_______ help you keep fit.
小题4:Problem kids need to be e_________ by teachers and parents.
小题5:Among the flowers stands a sign which reads, “No P______!”.
对于三侧均有电源的升压变或高中压两侧均有电源的降压变，其中压侧方向元件的电压应取自
A、高压侧或中压侧
B、高压侧或低压侧
C、中压侧或低压侧
