(Continued) exposure to stress has been linked to (worsened) functioning of the immune system, (leaving) a person more liable (for) infection.

单项选择题The (ruling) party could even lose (its) majority in the lower house of parliament, (started) a period of (prolonged struggling.)

单项选择题The ideal listener stays both (inside and outside) the music at the moment it is played and (enjoying) it almost (as much as) the composer at the moment he (composes.)