他什么时候改信伊斯兰教？

When did he ___convert to Islam?

弗雷德里卡改信天主教，并致力于照顾精神有问题的儿童。

Frederica ___converted to Catholicism and devoted her life to mentally ill children.

经过深思熟虑，他选择改信犹太教。

After much reflection, he chose to ___convert to Judaism.