Now 70 years old, the British physicist, Pendry can’t remember a time when he was not asking a question as a kid, joking that he ________ his parents to death.

A．should torment(折磨)

B．must torment

C．must have tormented

D．should have tormented

可以防治油菜“花而不实”的主要微肥是（）。

A、锌肥

B、钼肥

C、硼肥

D、铁肥