吸毒者也有遗传成分?

be known to为…所熟知
例句：The actor is well known to us.
我们熟知这个演员。

2. But Karen Esche at the University of Cambridge in Britain says the brain abnormalities found in addicts and their non-addicted siblings suggest these congenital differences might be to blame for the increased vulnerability to drug abuse.

blame for因…怪罪, 责怪(某人)
例句：He blamed his brother for breaking the window.
他责备他兄弟打破了窗玻璃。

3. “Which again puts them at risk of taking drugs, because what we see in addiction is that that self-control gets lost," Esche says.

at risk有危险
例句：The disease is spreading, and all children under five are at risk.
这疾病在蔓延, 五岁以下的小孩都有危险。

4. Nora Volkow, director of the U.S. National Institute on Drug Abuse, says the study suggests the brain abnormalities observed in the addicted sibling are not due to chronic and repeated drug abuse.

due to由于，因为
例句：Her absence is due to illness.
她因病缺席。