点拨：{#blank#}1{#/blank#}意为"过去常常"，后面接动词原形，表示过去存在的状态或发生的动作，但现在不再是这样了。

如：我过去常常和我最好的朋友去钓鱼。   {#blank#}2{#/blank#}

注意：{#blank#}3{#/blank#}意为"习惯于做某事"，{#blank#}4{#/blank#}意为"被用于做某事"。

如：我的妈妈习惯于晚饭后散步。   {#blank#}5{#/blank#}

小刀被用于切物品。   {#blank#}6{#/blank#}

When you meet a new word in your reading, you can {#blank#}1{#/blank#} {#blank#}2{#/blank#} {#blank#}3{#/blank#} in the dictionary.

Sally's on the other phone. Would you please{#blank#}1{#/blank#}  {#blank#}2{#/blank#}?

{#blank#}1{#/blank#} impolite {#blank#}2{#/blank#} {#blank#}3{#/blank#} others waiting.

Because people {#blank#}1{#/blank#} {#blank#}2{#/blank#} too many trees, some animals don't have enough food to eat.