这项技术我以前学过，只是有点生疏，需要复习一下。

Zhè xiàng jìshù wǒ yǐqián xué guo, zhǐshì yǒudiǎn shēngshū, xūyào fùxí yíxià.

I learned this technique before; I'm just a bit rusty and need to review it.

虽然我们有几年没见，但一点也不觉得生疏。

Suīrán wǒmen yǒu jǐ nián méi jiàn, dàn yìdiǎn yě bù juéde shēngshū.

Although we haven't seen each other for several years, it doesn't feel awkward at all.

好久没说中文了，我有点生疏。

Hǎojiǔ méi shuō Zhōngwén le, wǒ yǒudiǎn shēngshū.

I haven't spoken Chinese for a long time, so I'm a bit out of practice.