可以说a green bean吗

green bean意为四季豆，是可数名词，单数可以说a green bean，但一般是复数形式green beans.

例句

Then I ate a green bean cause my mother said I should.

然后我吃了豆角因为我的妈妈说我应该吃。

For breakfast, we have Fried rice, potato and green bean soup.

今天我们早餐吃炒米饭、土豆和绿豆粥。

Selects the green bean from South America, South East Asia and Africa.

咖啡豆选自南美洲，东南亚和非洲。

Want to have a little bit faster and blossom, to bear more of the small green bean bar!

希望们快一点儿开花，结出更多的小绿豆吧！

Solid Species candy, biscuit, peanut, green bean, pistachio, cooked food, pickles etc.

固体类糖果、饼干、花生、青豆、开心果、酱菜、膨化食品等。