主語+系動詞+表語+動名詞
例如:
be busy doing 忙於做某事
The children are busy doing their homework. 孩子們正忙於寫作業。
be worth doing 值得做某事
The house might be worth buying.
那所房子也許值得買。
be/feel comfortable doing 
做某事(感覺)舒適的
I feel comfortable lying on the grass.
躺在草地上我感覺很舒適。