lt could't be used then.lt wasn't ___to use it.a.able b.allowed c.impossible d.possible

lt could't be used then.lt wasn't ___to use it.a.able b.allowed c.impossible d.possible
lt could't be used then.lt wasn't ___to use it.a.able b.allowed c.impossible d.possible

lt could't be used then.lt wasn't ___to use it.a.able b.allowed c.impossible d.possible
答案是d.
a.be able的主语是发出动作（use）者,例如I；
b.be allowed的主语是动词被动形态的宾语（it）,这里第二句对应为“It wasn't be allowed to be used.”；
第二句中的It是形式主语,不同于后面的it和第一句的It.
c.意思刚好相反,注意impossible和wasn't都表达否定.
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