浓烟呛人，让人难以呼吸。

The smoke is ___suffocating, making it hard to breathe.

她父母的过度保护让她感到窒息。

Her parents' overprotection made her feel ___suffocated.

地铁里闷热的空气让人喘不过气来。

The ___suffocating air in the subway made it hard to breathe.