电容器在正弦交流电压作用下，通过的电流与其两端电压的关系是电流（）电压90度。
参考答案：超前
根据所学知识归纳一下，河姆渡、半坡、大汶口三处遗址有哪些共同点和不同点。
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The stronger the ___________ is, the more quickly a person will learn a foreign language. That is to say, it is up to whether he has an interest in the foreign language.
A．inspiration
B．ambition
C．motivation
D．aspiration
