murmured

"The unhappy was upset about failing the history test. "

"My friend told me there was something in the box, but I didn't know what it was yet. "

"The student's discontent with the course material was evident in her low grades. "

"Do you need a gift for that special someone?"

"It is hard work to swim against the current."

"I took the express into town."

"He is a student of life."

"The distant thunder produced a low grumble that shook the windows. "

"Given that "indistinguishable" is an adjective, not a noun, here's a sentence using it correctly as an adjective: "The twins were so alike that their voices were almost indistinguishable." "

"My complaint about the noisy neighbors was finally heard by the landlord. "

"The beggar muttered words of thanks, as passersby dropped coins in his cup."

"Joe was always complaining about the noise made by his neighbours."