I think it's nadar because "va al mar" means he is going to the sea. Therefore, he would be going to swim.
True.
Museo is masculine and you can't change it to female it is one of the few words you can't change.
Estas oficinas! Is plural
For 1-6, all you have to do is conjugate the words by taking away the -ar at the end of the infinitive and adding the designated ending.
1. cantar, canto, cantas, canta, cantamos, cantan
2. preguntar, pregunto, preguntas, pregunta, preguntamos, preguntan
3. contestar, contesto, contestas, contesta, contestamos, contestan
4. practicar, practico, practicas, practica, practicamos, practican
5. desear, deseo, deseas, desea, deseamos, desean
6. llevar, llevo, llevas, lleva, llevamos, llevan
section two conjugate the infinitive like before, with the subject from the sentence
1. viajan
2. hablamos
3. llegan
4.dibujo
5. compra
6. regresan
7. termina (i think)
8. buscas
