她在添加细节之前先画出了脸的轮廓。

She drew the ___outline of the face before adding details.

屋顶瓦片是漂亮的粉红色，每一片都雕刻成心形轮廓。

The roof tiles were of a beautiful shade of pink, each carved in an ___outline of a heart.

在暮色天空的映衬下，群山的黑色轮廓清晰可见。

The dark ___outline of the mountains stood clearly against the twilight sky.