"The boy needs water."
Translation:Teastaíonn uisce ón mbuachaill.
Note to the course modifiers should they read this. Some of the exercises in section Prepositions-1 require Teastaigh, and reject Bí, ó for want; others require Teastaigh, and reject Bí, ó for need; and vice versa. There's an overlap in meaning, and the way these are modeled as of 2019-04-23 is frustrating a lot of learners.
Learners: in this particular case, both teastaigh ... ó and bí ... ó can be used for both want and need, with as far as I can tell a slight bias for teastaigh toward want and a slight bias for bí toward need. But for these exercises one sometimes has to memorize which answer each question wants and needs to get past it.
Except when it does.
Ní raibh uaidh ach sin - "that was all he needed"
Ní raibh uaidh ach gaoth an fhocail - "he only needed the slightest hint"
Ní raibh uaidh ach an leathchead - "all he needed was an excuse"
Nithe beaga atá uaim - "little things I need"
Níl uaidh ach an tsiocair - "all he needs is an excuse"