再问天山3-14

A scrub jay can remember when it cached a particular piece of food in a particular place, researchers have discovered, and tend not to bother to recover a perishable treat if stored long enough to have rotted.

1. tend not to bother to recover a perishable treat if

2. they tend not to bother recovering a perishable treat

3. tending not to bother recovering a perishable treat if

4. tends not to bother recovering a perishable treat

5. tends not bothering to recover a perishable treat if

 答案是D

搜了CD上的讨论，好像都在说bother的用法，我想知道这里为什么用tends，难道是和cached平行吗？还有researchers have discovered是作为插入语吗？

主语是A scrub jay,因此谓语用tends, tends和can remember并列

researchers have discovered是插入语,不影响句子结构

这题还真难啊，后半句我连意思都不明白？

I choosed A, cause I think "... can remeber, and (can) tend..."

can -- ellipsis

if stored long enough to have rotted

真实条件句我觉得不能省略主语