mistakes

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

"My sister is learning to play the guitar. "

"My teacher explained the new math concept, and I understood it perfectly. "

"In her English class, Maria learned that a participle, like "running" in "running shoes," can act as an adjective. "

"My daughter's geography textbook covered the different climates of the world. "

"My unintentional comment hurt her feelings. "

"My sometimes neighbor, a retired teacher, still visits the school occasionally. "

"He intends to go to university."

"Everyone in the class needs to bring their textbook to the first lecture. "

"My sister misunderstood my instructions, and now the project is late. "

"The substitute teacher was very good at explaining the difficult math concepts. "

"The location of the school library is on the second floor. "