他的电话占线。

Tāde diànhuà zhànxiàn.

His line is busy.

我找不到他，他电话还在占线中。

Wǒ zhǎobudào tā, tā diànhuà hái zài zhànxiàn zhōng.

I can't find him, his line is still busy.

你的电话为什么每次都是占线？

Nǐde diànhuà wèishénme měi cì dōu shì zhànxiàn?

Why is your line busy every time?