他试探性地提出加薪的想法，想看看老板的反应。

He dropped a ___feeler about a pay raise to gauge his boss's reaction.

龙虾用触须探测周围的环境。

The lobster uses its ___feelers to sense the surroundings.

她天生敏感，总能敏锐地察觉朋友的情绪变化。

She's a natural ___feeler, always sensing her friends' emotional changes.