—I’d like to invite you to my new house next weekend.

—Thank you, but ____ I’ll have time I’m not sure at the moment.

A．when

B．as

C．in case

D．unless

预防结核病的化学药物，最好采用下述哪个药物

A．乙胺丁醇
B．PAS
C．利福平
D．异烟肼