zài / huìzhì / jiànzhù / túzhǐ / shí / yào / xiān / yòng / qiānbǐ / huàchū / lúnkuòxiàn

在绘制建筑图纸时，要先用铅笔画出轮廓线。

When drawing architectural blueprints, you should first sketch the outline with a pencil.