_________is very interesting to swim in the river in summer, but it’s dangerous.

This exerciseis difficult . [ ]

Dad, I can’t open my e-dictionary in my computer.—You can _____ the computer and try again.

I called you yesterday afternoon, but there was no reply.—I ______ a dolphin show the zoo with my cousins.

Is this a photo __________ your friend?-Yes, it is.[ ]