英语上有一些单词既是及物动词又是不及物动词

及物动词不带宾语，就是不及物动词。

eg.
I work hard 我工作努力。 不及物
I work the wood. 我加工这木头。 及物
accumulate
1.累积,积聚;积攒
They set to work accumulating a huge mass of data.
他们开始累积大量的资料。
I was accumulating my money to buy a new bike.

不及物动词 vi.

1.积成堆;累积,聚积
Dust had accumulated during her absence.
她不在时灰尘
Spider nets had accumulated on the surface of the ceiling.

1.
我给汽车加速 I accelerated the car.
汽车加速前进 （这时候没有宾语） The car accelerated.

2.
及物： He accumulated a big sum of money. 他攒了一大笔钱。（宾语是 a big sum of money)

不及物：the snow accumulates quickly.