Now comes the real test for Mitch Trubisky.

After acing the open-book quiz against the Lions, Trubisky has to get out the blue book and take an all-essay exam against the Cowboys on Thursday night at Soldier Field. And this one is much more than one-sixteenth of the final grade.

Trubisky is coming off one of his best games of the season. He completed 29 of 38 passes for 338 yards, three touchdowns and a 118.1 passer rating.

It was his second-highest rating of the season. But considering it was on the road on a short week, with bigger passing numbers that included a 90-yard game-winning drive in the final 6:40, it was his best performance. After throwing an interception in the third quarter, Trubisky completed 10 of 11 passes for 165 yards and two touchdowns on drives of 80 and 90 yards for a perfect 158.3 rating.

A year ago, as a developing quarterback in his first season in a developing offense under coach Matt Nagy, that kind of performance would have been hailed in some corners as the arrival of Trubisky. Or a harbinger of the arrival of Trubisky. But not this time.

A year later, there was as much skepticism as there was celebration. And for good reason. We’ve seen this movie before. Trubisky’s last efficient game was against the same Lions at Soldier Field — three touchdowns no interceptions and a season-high 131.0 rating. The following week, against a better defense, Trubisky was back to normal: 23 of 43 for 190 yards, one touchdown, one interception and a 65.1 rating against the Rams at the Los Angeles Memorial Coliseum.

As well as he played against the Lions last week, Trubisky didn’t change any minds. He’s good against a defense that plays into his hands by playing man-to-man defense with only one above-average cornerback — Pro Bowl player Darius Slay. The acknowledgement that Trubisky played a big-boy quarterback game — reading defenses, going through his progressions and making pinpoint downfield throws — was offset by the questionable degree of difficulty. His protection was mostly excellent. When it comes to painting-by-numbers, Trubisky can be a master.

Now, he gets to show he can work in a little more of an abstract realm. Against the Cowboys, the pocket is more likely to be chaotic than clean. “These guys are elite, elite, elite in that [pass-rushing] regard,” Bears offensive coordinator Mark Helfrich said. “Every O-line gets beat by these guys; every quarterback gets sacked by these guys, gets hit by these guys and you have to weather that storm.

“You have to step up and get it out; you have to step up and run. Everybody has to be on the same page from the [aspect] of what’s the protection? How are we doing the various types of things we need to do from these guys? And just execute.”

If Trubisky can do that, there will be opportunity. Last week, the Bills’ Josh Allen, ranked 20th in the NFL in passer rating, threw for 243 yards, a touchdown and a 120.3 rating — his best of the season — in a 26-15 victory against the Cowboys at AT&T Stadium.

Is Trubisky ready for that? Can he operate efficiently within the chaos?

“In progress,” Helfrich said. “He’s certainly not perfect by any stretch, but that’s an 11-person deal. That’s a scheme thing and we have to help him through that — trust in the rhythm of what’s there and realize that a throwaway is probably going to happen against these guys. Josh Allen made some spectacular plays, but he also had some throwaways, some runs. So it’s the full gamut of all that stuff.”