Sunken slabs of ocean crust block flowing rock from moving further sideways, forcing it to turn downward and sink.

沉没的大洋板块阻止岩流向更深处移动，迫使它向下沉。

Then their fortunes took a downward turn.

然后，他们的命运发生了转机。

From then on, our fortunes took a downward turn.

【turn】从那以后，我们的际遇每况愈下。

It was so close that Laura saw its cruel round eye turned downward to look at her.

它离得太近了，劳拉看到它残忍的圆眼睛向下看着她。

The transverse colon passes horizontally to the left toward the spleen and turns downward (splenic flexure) to the descending colon.

横结肠水平向左面朝脾脏，向下（通过脾曲）成为降结肠。