Definition: used to talk about how someone often behaves or what something is often like Level: B2
一旦他拿定主意，有时会相当固执。
He ___can be quite stubborn when he's made up his mind.
周末的公共交通有时不太靠谱。
Public transportation ___can be unreliable on weekends.
这里的夏季天气有时会非常难以预测。
Summer weather here ___can be very unpredictable.
