1.   And so the question of what accounts for the dark matter remains appropriately up in the air.

2.   Because the deal was struck with great speed, it is perhaps understandable that a number of important details remain up in the air.

3.   Accommodation arrangements remain up in the air, to the frustration of many.

4.   Bush has embraced the Saudi approach in general, stressing that the details of an Israeli-Palestinian peace accord remain up for negotiation.

5.   But anything beyond that remains up to Springsteen.

6.   But the question of back pay remained up in the air.

7.   But traders said the trend for the dollar remained up.

8.   Details remain up in the air.

9.   For them as well, too much remains up in the air to second-guess the wisdom of hanging tight.

10.   He expects demand to remain up at least for the rest of the year.