these共4篇 these days用于什么时态these days用的时态包括一般现在时、 现在进行时、现在完成时、现... are these的肯定回答和否定回答are these的肯定回答是Yes，there are 是的，有。否定回答是No,there aren't 不... these days用于什么时态these days用的时态包括一般现在时、 现在进行时、现在完成时、现... are these的肯定回答和否定回答are these的肯定回答是Yes，there are 是的，有。否定回答是No,there aren't 不...
