Ceacht 7
sa 	in the	prep.incorporating article ( =i+an) 	
sa bhaile	at home	[prep.incorp. art.] + [n m4 #len.#]	
sa chistin	in the kitchen	[prep.incorp. art.] + [n f2 #len.#]	
sa teach	in the house	[prep.incorp. art.] + [n m2]	
sa leaba	in the bed	[prep.incorp. art.] + [n f5]	
sa seomra	in the room	[prep.incorp. art.] + [n m4]	
sa scoil	in the school	[prep.incorp. art.] + [n f2]	
an bhfuil sé	is he, it?	[int. part.]+[pres dep v #ecl.#]+[sg. pron]	
tá sé 	he/it is	[v] + [pron]	
níl sé 	he/it is not	[v] + [pron]	
ann	there, in it	adv	
maith go leor	good enough	[a.] + [adv.]	
dona go leor	bad enough	[a.] + [adv.]	
slán agat	good-bye( to person staying)	(health) [n m1]+[prep. pron. ]	
slán leat	good-bye (to person leaving)	(health) [n m1]+[prep. pron.]	

In Lesson 3 we saw an example of a question with "Níl Seán leat inniu?" which literally means "Seán isn't with you today?"  This format of turning a statement into a question simply by adding a question mark at the end in writing, or a change in tone of voice in speech, is quite common in English but it is incorrect in Irish, despite what the book says in Lesson 3.  
To be strictly correct in English we should move the verb to the front and ask "Isn't Seán with you today?" and Irish has similar rules which should be followed.  The correct way to ask a question in Irish is to employ what is known as an interrogative particle, such as "an" in a positive question as we saw in Lesson 5.  As we know, "an" causes eclipsis of the verb so the positive question "Is Seán with you today?" would be "An bhfuil Seán leat inniu?". 

"Sa" (in the) causes lenition to the consonants b, c, g, m and p, so we'll see sa bhaile (lit. in the home) but sa teach (lit. in the house) etc.

agat, leat:  These words literally mean at you and with you respectively when referring to one person.