是at the beginning of 还是at beginning of

at the beginning of
at the start of
这种东西都要加the的
还有比如
at the end of

at first是没有the 的

at beginning of 这个没有见过。。。应该是at the beginning of
At the beginning of the term, I found it difficult to study English.
在这学期初, 我觉得学英语很困难。

should be 'at the beginning of '

有“the”的
习惯说法