With a sigh, she did what she swore she’d never do. She opened her desk drawer, pulled out the slim, stapled booklet, and flipped to Unit 7.
The ground is wet. It must have rained. She pictured dark clouds, an umbrella forgotten on the bus. He’s not here. He might have been delayed. She imagined a broken-down train, a phone with a dead battery. Each wrong guess—she wrote should have rained first, then crossed it out—taught her something the answer key never could: why .
There it was. Page after page of neat, black type. For sentence four: must have rained .
“Maya,” he said, pushing his glasses up. “These are excellent. So tell me… why did the speaker in sentence eight say the thief can’t have used a key ?”