1. Don't be such a dunderhead and read the instructions before assembling the furniture.
在组装家具之前，别做个傻瓜，先读一下说明书。
2. My boss can be a real dunderhead sometimes, making foolish decisions without thinking.
我的老板有时真是个大笨蛋，不经思考就做出愚蠢的决定。