How do you say

Jack is running a marathon in three months.

..in Chinese?

杰克在三个月内将参加马拉松比赛。

jié kè zài sān gè yuè nèi jiāng cān jiā mǎ lā sōng bǐ sài 。

How do you say "It snows in Beijing in winter, and it can get very cold." in Chinese?