1. Tosfos on the bottom of 3b asks why we need a gezeira shava to teach us that two witnesses are required in a normal case of a woman committing adultery ( ie. no kinuy or stira)- he basically says that it is obvious that you need 2 and that you wouldn't think that one would be sufficient like it is in the case of Tumah when there was kinuy and stira because there you have regalim whereas in the normal case there are no regalim. It seems like tosfos leaves the question unanswered. Am I learning the tos wrong? Is there an answer to tosfos question? Please let me know.

2. On 4a the gemara goes through the stages of what is the shiur of stira and basically says - kedai tumah, kedai biah, kedai haarah, kedai hakafas dekel and explains why all the words need to be mentioned. Rashi asks on the phrase of hakafas dekel if at the end of the day the shiur is kedai hakafas dekel the just write that and all we be well. Rashi answers that while that is true if it only wrote hakfas dekel it would be unclear if the gemara was concerned about the stira leading to haarah or gemar biah- and that is why it listed all the phrases. However, Rashi earlier on the daf quotes the gemara in yevamos which says that haarah is considered like gemar biah with respect to all the arayos listed in the torah. If thats the case then all the gemara would have to write was kedei hakafas dekel-and we don't need any extra limudim to indicate that all we are concerned with is haarah since we know that already from the gemara in yevamos.

ari, USA