299.He knows that even if he gets a dog pregnant, the offspring, should they survive, will face the problems shown at birth by other cloned animals: abnormalities like immature lungs and heart and weight problems.

他知道，即便他让一只狗怀孕，其后代（如果能存活的话）将面临其他克隆动物在出生时所出现的问题：畸形发育，如肺部和心脏不完全发育以及体重问题。

六级词汇讲解:

本句的主干是He knows that...。nows后面的内容均为that引导的宾语从句；该从句中包含even if引导的让步状语从句；should they survive为插入语，是虚拟语气，因省略了if而引起倒装，过去分词短语shown at birth by other cloned animals作定语修饰problems，冒号后的内容对其进行补充说明。

英语六级考点归纳
even though和even if均可用于引导让步状语从句，但有细微区别。
even if意为"即使；尽管；纵然；就算"，引导的从句往往是假设性的，有时还可用于虚拟语气；此时even if与单独使用的if比较接近。如：
Even if many difficulties remain，we can overcome them.
即使有再多的困难，我们也能克服。
Even if it should snow tomorrow，they will go jogging.
纵使明天下雪，他们也要去跑步。
I would have married him even if he had been penniless.=1 would have married him ifhe had been penniless.

即使他身无分文，我也会嫁给他。

even though意为"尽管，虽然"，引导的从句内容往往是真实的，主要用于引出不利于主句情况的信息，相当于although，在非正式的情况下可以省略 even。如：
( Even) though it is twenty years old，the house is still in good condition.
虽然这栋房子已经有20年房龄了，但它的状况仍旧良好。
I don't want to eat anything，(even) though I am hungry.
尽管我很饿，但我还是不想吃任何东西。
( Even) though Nick was tired, he helped me repair my computer.

尽管尼克累了，但他还是帮我修了电脑。

在实际语言运用中，even if与even though有时也可不加区别地混用。如：
Even though/if you do not like your job，you must do it．
即使不喜欢你的工作，你也得做下去。