英语四级题目When Louise Brown was born on 25 July 1978,she kicked

英语四级题目
When Louise Brown was born on 25 July 1978,she
kicked off an era.The first “test tube baby” is a mother herself now,and she’s
been joined by millions of others born with the ___47____ of in vitor
fertilization (体外受精),or IVF.Now
specialists wonder whether people who were conceived by IVF are likely to be
___48____.
“By and large,the kids are just fine.It’s not
like the kids having ___49____ arms or heads,” says Carmen Sapienza,a scientist
at Temple University.But none is older than their early 30s,and the vast
____50___ are under the age of 20,so they have not had time for long-term
health problems to show up.
One source of worry is that so many IVF babies
have low birth weight,children-conceived through IVF are more likely to ___51__
less than 2.5 kilograms than are babies conceived ___52____.That could spell
trouble ahead,because low-birth-weight babies often have long-term health
problems.They are more likely to be obese,to have diabetes or other
problems.
With that in mind,Sapienza and colleagues have
looked at genes that are likely to play a role in such health problems.They
found that certain DNA-patterns,which affect how genes are ___53___,are
different between IVF and non-IVJ children.There is no way to tell if that is
because of the ___54____ used to produce the IVF babies or whether the
difference has something to do with the underlying infertility problem the
parents had.It is also ___55____ whether these gene-expression differences will
translate into health differences.But is does suggest that children conceived
by IVF are ___56____ on some level.
A) weigh B) technology C) help D) unsure E)
unclear
F) naturally G) expressed H) procedure I) unique J)
healthy
K) explained L) extra M) majority N) minority O)
completely

B.J.L.M.A.F.G.H.E.I