effort的用法?是什么时候单数 什么时候复数?make great efforts to do 还是effrot?

effort的用法?是什么时候单数 什么时候复数?make great efforts to do 还是effrot? make all effort 还是efforts? make efforts to do sth.为什么effort要加s? make efforts与make an effort的区别是什么 make efforts/an effort to do和in a common effort Make great efforts to only be capable to do success 一个英语词组的疑惑,是to spare no efforts to do还是to spare no effort to make efforts to do sth.为什么effort要加s,它是可数名词吗? 是spare no effort to do还是spare no efforts to do? make effort to/ make efforts to 哪个对? 英语翻译不遗余力做什么事情的英语说法是spare no effort to do 还是 spare no efforts 是make no efforts还是 make no effort?