不能超过英文

因为是游戏的环境，输入节省时间，可以直接说:Watch your time.正式的说法是Don't overstep the time limit.

in 30 days 30天内,都是这么用的

1、至多at (the) most(adv) upper limit; at mostnot more thanat the utmostat the outsideat the longestB not more thanat the mostat the very mostmax.例子：他只是短期外出--至多一周。 He's only away for short periods a week at the longest.它想他至多不过15岁。 I think he was fifteen at(the) most.一晚上我至多可挣250英镑。 At (the) most I might earn 250 a night.我们每周至多工作四十小时。 We have 40 hours at work at the most each week.2、最多maximumat (the) mostlargest (number of sth)the mostmostat bestat the outside例子：这间小屋最多能容纳5个人。 The cottage could accommodate up to five people.我们最多给百分之四的佣金。 A4%25 commission is the maximum.整个来说，我们队得分最多。 Our team scored the most goals on aggregate.我父母死时她给我的帮助最多。 She helped me (the) most when my parents died.这厅最多容纳七十人。 This hall holds a maximum of seventy people.3、不超过at the mostnot more thanno more ... than ...not exceeding例子：我参加聚会的时间必须不超过两个小时。 I must limit myself to two hours here in the party.最远不超过十英里。 It's ten miles away, at the farthest.我将待在这里最多不超过三天。 I'll stay here not more than three days.

less than 30 days.not more than 30 days.

at most, no less than, at most, at most, no more than.

sth. cannot be beyond 30 days.