要看具体语境，effort在某些情况下可数，在某些语境下不可数，如果可数，用a lot of efforts 如果不可数用a lot of effort因为a lot of 要么跟可数名词复数要么跟不可数名词。附：effort的可数与不可数effort（做某事物使用的）力量和精力的时候是不可数的.比如:They lifted the heavy rock without effort. 他们没费劲就把那块沉重的石头抬起来了.做可数名词的时候意思上有两种:1.努力; 奋斗(相当于attempt) 比如:His efforts were much appreciated. 大家都夸他很努力. 2. 努力的结果(相当与result of an attempt) 比如: That's a good effort. 这事干得不错.
