【推荐1】These days, teachers have been sparing no efforts to create         they hope will be the best means to improve the efficiency of online teaching,         some students don’t notice or care about, though.

A．that, which

B．what, which

C．which, what

D．what, that

【推荐2】The great majority of research on the topic has been observational, ________ we just look at ________ happens to people who do and don’t drink coffee.

A．meant; which

B．meaning; what

C．which meant; what

D．meaning; which