If a four-Tefach plank always invalidates a Sukah, then why does R. Meir allow Sechach when there is an equal amount of space as the Pasul boards between each board?

1.   ?    Thats in the Beraisa.
2.   ?    הלכה למשה מסיני
3.   ?    איבעיא דלא איפשטא
4.   ?    They are within the four Amos limit for Dofen Akumah, leaving an eight Tefach Kosher Sukah. (the 'open' from each side meet in the middle)
5.   ?    Machlokes A&D.

Will the Sukah be Kasher if one fills in part of a space of three Tefachim in the S'chach, with metal rods?

1.   ?    Yes.
2.   ?    No.
3.   ?    Only in a large one.
4.   ?    C,Machlokes A&B.
5.   ?    Machlokes A&C.

If a room has a Tefach by Tefach skylight, an object that is directly underneath the skylight remains Tahor, if there is a piece of corpse in the room. What if the Tumah is under the skylight?

1.   ?    Everything is Tahor.
2.   ?    Everything is Tamei.
3.   ?    Everything is Tahor if it is flesh not bone.
4.   ?    Sofeik.
5.   ?    Machlokes A&C.

Can we learn Sucah from here.

1.   ?    Yes, we can always learn from a הלכה למשה מסיני.
2.   ?    Yes, only Succah as they are both הלכה למשה מסיני.
3.   ?    No.
4.   ?    Machlokes A&B.
5.   ?    Machlokes A&C.

סיכך על גבי אכסדרה שאין לה פצימין ie a portico with no uprights.

1.   ?    Fine, we always say פי תקרה יורד וסותם .
2.   ?    Fine here we say פי תקרה יורד וסותם as it has a דופן .אמצעי
3.   ?    False.
4.   ?    Machlokes A&B.
5.   ?    Machlokes B&C.

It is permitted to carry on Shabbos inside an Achsadra that is not near a house because Pi Tikrah Yored ve'Sosem.

1.   ?    True.
2.   ?    False.
3.   ?    Exactly like Succah.
4.   ?    Sofeik.
5.   ?    Machlokes A&B.