Question

【题目】Once you ______ the knack of it, you will have no further difficulty. ( )

A.shall haveB.had hadC.are havingD.have

Answer 1

【答案】D

【解析】

句意：一旦你掌握了诀窍，你就不会再有任何困难了。主句用一般将来时，从句用一般现在时。故选D。