Manuel, ¿ un lápiz o un bolígrafo? (necesitar)
a.

necesito

c.

necesitamos
b.

necesitas

d.

necesitan

adela, ¿ dos lápices o tres? (comprar)
a.

compro

c.

compran
b.

compramos

d.

compras

él un disquete.
a.

buscamos

d.

busca
b.

busco

e.

buscas
c.

buscan

señores, ¿dónde uds.? (trabajar)
a.

trabaja

c.

trabajan
b.

trabajamos

d.

trabajas

yo un bolígrafo.
a.

buscamos

d.

busca
b.

busco

e.

buscas
c.

yo un bolígrafo.
a.

buscamos

d.

busca
b.

busco

e.

buscas
c.

buscan

señor, ¿ud. el alemán? (hablar)
a.

hablan

c.

hablamos
b.

hablas

d.

habla

marcos y yo un cuaderno.
a.

buscamos

d.

busca
b.

busco

e.

buscas
c.

buscan

señorita, ¿qué ud. en la tienda? (buscar)
a.

busca

c.

busco
b.

buscas

d.

buscan

necesito is the conjugation of the verb necesitar for the first person singular in the simple present. The simple present tense is used to talk about habitual actions or routines. This tense is also used to describe things that happens now or in the near future. So the subject pronoun that matches the first person singular is yo (I). Therefore, I address Manual asking if I need a pen or pencil.

compro is the conjugation of the verb comprar for the first person singular in the simple present. The verb comprar translates into to buy. On the other hand, lápices is a masculine and plural noun. So I address Adela asking if I need to buy two or three pencils.

busca is the conjugation of the verb buscar for the third person singular in the simple present. So the subject pronoun that matches the third person singular is él that translates into he. On the other hand, disquete means floppy disk. Hence Él busca un disquete translates into He looks for a floppy disk

trabajan is the conjugation, in the simple present, of the verb trabajar for the second person plural. This subject pronoun for the second person plural is ustedes. In Spain, this subject pronoun is used in formal form while in other Spanish speaking countries this is used in both formal and informal way.

busco is the conjugation of the verb buscar for the first person singular in the simple present. On the other hand, bolígrafo is a masculine and singular noun. The word un is an indefinite article.Indefinite articles are used to talk about something that is not defined. The indefinite article that matches masculine and singular nouns is in fact un. Hence Yo busco un bolígrafo means I look for a pen

The same question as in 5.

habla is the conjugation, in the simple present, of the verb hablar for the second person singular in formal form. This subject pronoun for the second person singular in formal way is usted. So usted translates into you but in formal form. Hence Señor, ¿Ud. habla el alemán? translates into Sir, Do you speak German?

buscamos is the conjugation, in the simple present, of the verb buscar for the first person plural. This subject pronoun for the  first person plural is nosotros whose translation is we, that is, Marcos y yo can be replaced by nosotros. Hence the sentence Marcos y yo buscamos un cuaderno translates into Marcos and I are looking for a notebook.

busca is also the conjugation, in the simple present, of the verb buscar for the second person singular in formal form. Since I am addressing a miss respectfully, we need to use the subject pronoun usted. Therefore, the sentence Señorita, ¿qué busca Ud. en la tienda? means Miss, what are you looking for in the store?

there is no "following"