During the third month of pregnancy the sex of the child becomes determinable.

孩子的性别在妊娠期第三个月便可查明。

《牛津词典》

That brings me to the third area of research which fails to support single-sex schooling and indeed suggests the practice is actually harmful: social developmental psychology.

这让我想到研究的第三个领域，它并不能支持单性别学校教育，而且实际上表明这种做法是有害的，那就是社会发展心理学。

youdao

There is an interesting thing with the eunuch, who's the third sex character that Meera Syal develops.

BBC: Bombay Dreams

And Mobiledia reported here earlier that one third of Americans prefer smartphones to sex.

FORBES: After I Dumped My Smartphone - 25% Wealthier But Showing Signs of Weakness

The LTBB is the third tribe to recognize same-sex marriages, after the Coquille Tribe of Oregon and the Suquamish Tribe of Washington.

CNN: Tribe marries same-sex couple but state won't recognize it