8,  After crossing the equator, the captain called in at a port to have a new rudder fitted, but by now the Thermopylae was over five hundred miles ahead.
all in at: （船）停靠，（人）拜访
     to = in order to, so as to “目的是”
 
9,  Even this was remarkable, considering that she had had so many delays
considering 连接词，用来引导完整的语句
     considering that考虑到………
     So we should forgive him considering that he is ill badly.
 
10, There is no doubt that if she had not lost her rudder she would have won the race easily.
There is no doubt that...==without any doubt “毫无疑问“
     There is some doubt + wh- ...
Eg.: There is no doubt that he is guilty.
There is some doubt whether he is guilty.
if ----与过去事实相反的虚拟
（二册L71 P320）：If the Houses of Parliament had not been burned down in 1834, the great clock would never have been erected.
If you talked less and ate more, we would both enjoy our dinner. (二册：L40 P182).
 新概念英语第二册视频