ShipscarrylifeboatsthecrewcanescapetheshipsinksA.soasto,ifB.sothat,unlessC.sothat,ifD.inorderthat,incasethat请大家详细解答分析,谢谢详细分析BD,为什么不选BD?unlessincasethat可以啊答案是C

Question

Ships carry lifeboats ____ the crew can escape ____ the ship sinks
A.so as to ,if
B.so that ,unless
C.so that ,if
D.in order that ,in case that
请大家详细解答分析,谢谢
详细分析BD,为什么不选BD?unless in case that可以啊
答案是C

Answer 1

答案选C
目的从句,如目的所指的人与主句中的主语不同,或原主语再次被提到,则必须使用目的从句：Ships carry lifeboats so that the crew can escape if the ship sinks．
大船上带有救生艇,万一船下沉船员可以逃生.
unless=if not,意思不正确,不符合逻辑