Question

_____________ all the seats were full, he had no choice but to stand up.

A．For

B．As

C．Though

D．Unless

Answer 1

B

考查连词的用法。For 因为，只能放在句中不能放在句首，As 因为，Though 虽然，Unless 除非，句意：因为所有的座位都满了，他别无选择除了站着。所以选B。