placid

即使面对吵闹的孩子，这位老师依然保持平静。

Even with noisy children around, the teacher stayed ___placid.

高山湖泊平静的水面以镜子般的精确度倒映着四周山峰，湖面几乎看不见。

The ___placid surface of the alpine lake reflected the surrounding peaks with mirror-like precision, making the water nearly invisible.

那只安详的老狗整个下午都躺在门廊台阶上，邮递员经过时几乎连头都懒得抬起。

The ___placid old dog lay on the porch step all afternoon, barely lifting its head when the mail carrier walked by.