Help me please with this exercise

A Superhero is a fictional character with special powers. (1)___Since __________ the first Superman story was written in the USA in 1938, superheroes have (2) _appeared__________ in various comic books around the world. But more recently they have (3)__become__________ better known as film characters.



(4)__although ___________ superhero powers vary widely, superhuman strength and the ability to fly are common. (5)_Some _________ superheroes do not have special powers but have (6) __developed_________ other important abilities. In order to protect friends and family, a superhero’s identity is normally (7)__kept_______ secret, which often means superheroes have a complicates double life.



(8)____ There  __________have been successful superheroes in countries other than the USA. Examples (9) ______include________ Cybersix from Argentina and the heroes of AK Comics from Egypt. Japan is the only country that has created as many superhero characters as the USA, most Japanese superheroes are short-lived. While American entertainment companies reinvent superheroes, (10) ___hoping__________ they will stay popular, Japanese companies frequently introduce new characters.



1.a) Until b) Since c) From d) Before (Since makes the most sense; it refers to something from the past)
2.a) shown b) entered c)come d) appeared (have appeared, present perfect tense always has -ed endings)
3.a) become b) returned c) changed d) grown (become, needs to be in the present tense, referring to the characters in the current time period)
4.a) because b) if c) although d) so (good job!)
5.a) Each b) Some c) Another d) Both (Some, refers to a portion of the characters, not all) 
6.a) made b) increased c) prepared d) developed (good job)
7.a) held b) put c) kept d) got (good job!)
8.a) These b) That c) There d) Those (There, there refers to the fact that they exist)
9.a) consist b) involve c)contain d) include (while involve makes sense, include is the correct answer (English speakers often say "Examples include")
10.a) hoping b) requiring c) needing d) asking (good job!)

Hope this helps!