We often hear the baby____________in Room 302
A.cried  B.cries C.to cry D.cry

大家选什么？为什么？.

D.cry
动词hear属于感官动词，后面常跟省略to的动词不定式。
再如，I saw him play the guitar in the singing room last night.同理。

感谢楼下指正！我上面一句例子没说清楚。
I saw him play the guitar in the singing room last night。我昨晚看到他...弹吉他了。
如果换成，
I saw him playing the guitar in the singing room last night.我昨晚看到他...在弹吉他。
概括起来，感官动词（如hear,see）常用于下面两种“接宾语，再接宾语补足语”的结构中：hear+sb+do/doing。其中前者，强调听到过某人做过某事；后者，强调听到某人在做某事

[ 本帖最后由 成长不烦恼 于 2008-9-7 22:55 编辑 ].

选D
hear 的用法有两种，hear sb do和hear sb doing
如果是经常发生的事情用 do 正在发生的事情用doing
如果是全过程是do ,部分过程是doing
这道题是经常听到小孩哭，所以用cry

成长不烦恼所举的例子在考试做选择题是错的，应该是I saw him playing the guitar in the singing room last night.

hear is a feeling adjective.It often uses in two ways.
if you hear the whole of baby crying.you need use"crying"
if you don't hear the whole,you only hear in often,you need use "cry".
CHOOSE ''D'.

高手云集！！！.

选D，凭感觉.