Vitamin D helps our bodies make a special chemical, and this special chemical, ______, affects our brains, making us feel happy.[ ]

ike a double room with a view ,please.—I’m sorry, but all double rooms with asea view _____________already.

His English, ______ used to be very poor is now excellent.

Everyone agreed that the suggestion he________ at the meeting________. [ ]

Middle school students hardly know anything aboutshopping online, ____ they? — ________. It’s very popular withteenagers.